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4.7 liter misfire & I'm stumped

104K views 13 replies 5 participants last post by  jamied723 
#1 ·
Hello, first post here :smileup:

I have never owned a Dodge before so hopefully you dodge experts can chime in & point me in the right direction.

I just purchased a 2005 Ram 1500 quad cab with the 4.7 liter engine, I have googled hundreds of websites for answers and it seems that the 4.7 is a less than reliable engine (according to the search results) I hope this isn't true.

When I bought the truck it ran great, passed emissions great and then the next day it started missing, It's cylinder #3 per the OBDII scanner & my own trouble shooting.

I pulled the #3 coil pack plug off & no difference, pulled the #3 injector plug off & no difference, swapped coil packs, injectors, plugs from next cylinder over, no difference, the cylinder is dead, I even swapped injector plugs from adjoining cylinders, still no difference.

I didn't want to spend a bunch of money on parts so swapping the parts from another cylinder will do just as well for trouble shooting.

After reading everything on the web I'm getting worried about a burnt or stuck valve. So I ran a 1/2 pint of SeaFoam through the brake booster hose and shut her down for 5 minutes. Of course on re start I smoked out the neighborhood. I also added 8 oz of Marvel Mystery oil to the oil and hoped it may unstick a valve if it was stuck in the first place.

I took her out on the freeway and really blew her out, the miss starting getting really bad and I got the check engine light again, code P0303 misfire cylinder #3. Then all of a sudden it stopped and started running perfect again.:4-dontknow:

I left the engine running and wiggled everything near #3, injector, coil pack, etc. still ran great. I shut her down & cleared the code & she ran fine the rest of today.

So... My question is what the heck caused it? Was the valve sticking and the Seafoam/Marvel oil freed it up or was it something else? It's got me very nervous now. The engine has 95,xxx on her & I purchased the truck from the original owner who was good friends with a tech at the local Dodge dealer so all maintenance was performed on time. He told me that he never had any trouble & the MIL had never came on before ever.

Could it be carbon build up on the valves? or am I going in the wrong direction? The only other thing I can think of would be the ECU wasn't sending a signal to that one coil pack but that's a long shot.

Also on cold start up you can hear faint tappet sounding noise on the top end for about 1 minute. The Dodge tech said it's completely normal until the oil pressure builds up on the 4.7 liter. Is this common? The oil pressure gauge shoots right up to the normal operating range. I read online that the tapping noise is from carbon build up on the valves, true or false?

Any input is welcome, Thanks Rich
 
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#2 · (Edited)
4.7 seem to have it's pro and cons but if well taking care of it could be like no other.
My advice is to do a compression test on all cylinders and get your self a DIY ignition Tester to check all the electrical connectors for power during idle and acceleration. Get an PCM update of the latest Firmware to correct all the Error's that the Stock PCM came with from Factory. I did mine and it corrected many of the issues I hade with the PCM and TCM. As far as for the tapping in morning it's kind of normal for some people. I just Rebuild my engine completely and I mean everything. I have no more tapping and knocks at all not even in the morning. The tapping you hear is a little wear and the valve adjusters drain from all the oil so it will take time for the oil to build up pressure again to get them full of oil . You might wanna start getting replacements as for every morning it a dry start building up into failed cam lobes in the future. Many will disagree but I seen many 4.7 fail due to lack of oil. Once you check all the cylinders and get the compression test result try to get an injector light tester to get reading on when the injector comes on. These diagnostic I think will get you right on the page you want. let me know how it goes. Good luck
 
#3 ·
Well I really like the the truck but after reading all of the horror stories about the Dodge engines (all of them) I think it's best to sell it and re coupe my money while I can. It's running great now but there is nothing except negative on the web about Dodge power plants. I guess that's why Ford's & Toyota's hold there value and cost more. I should have done more research before buying it.

Thanks for the good advice, I do appreciate it. I'll know in a couple of weeks if I'll be keeping it or selling it.

Has any of these 4.7 engines went to 150-200k without issues? All I read is about 100k failures, rocker arms, head gaskets, oil sludge, valve seats, etc. It has scared me away from Dodge ownership.
 
#4 ·
these 4.7 are great engine is that some of us have brought the truck with abuse already but you can't tell until a problem pops up. Like with any engine it's things that could of been provented but previous owners never tried so now we got to fix what we got and make the best of it. I seen many 4.7 go over 180,000 without problems and I have been working on 4.7 for about 6 years now.
 
#5 · (Edited)
My 02 4.7 has 160,000 on it now and no sign of letting up. I was also nervous about my truck when I first bought it due to those reviews on the internet. The more you read them though, the more you realize that the writers view a vehicle as an appliance to just get them from A to B with as little maintenance as possible.

Sludge happens from not changing your oil. Yeah, yeah I know a lot of the reviews say the oil was changed every 3,000 on the dot, but what else would they say? The reviewer is certainly not going to admit laziness on oil changes and then bash the product when it fails admitting their lack of maintenance, especially where the dealership is involved. The 4.7 was built with smaller oil passages so the proper weight and oil change interval followed religiously is crucial. I run 5w30 synthetic and have had no problems regarding sludge. If you are concerned about the way it was taken care of before, do a couple short changes and run marvel mystery oil or a good cleaning synthetic (pennzoil platinum, mobil 1 etc) through it.

Popped head gaskets happen when this engine gets hot. Being a totally aluminum engine it is sensitive to heat, and if ran to into the red on the temp gauge its a question of when, not if it will toss a head gasket. Again, people tend to get lazy on maintenance of the cooling system because of the 5 year, 150,000 mile coolant that is made now. People just dont like to spend money on their cars its seems, and at $18 a gallon for this anti freeze it is no surprise that cooling systems are neglected more then they ever were. Simply flush your radiator every couple years, change your thermostat and make sure your water pump and belt is in good condition and you should be good to go. Of course repair any coolant related issues that may pop up as they come and not when they totally fail. I almost cost myself some money a year after buying my truck due to ignoring a leaking radiator. Little did I know at the time it was leaking because the radiator was clogged and one day while leaving work actually blew the rest of the seal and all of my coolant. Luckily I was able to catch this before it got too hot and was close to work and able to repair the next morning.

The 4.7 is a reliable engine but also requires maintenance. If you take care of it, it will take care of you. A lot of the hemi guys dog it because it is not a hemi, what they dont know is that by definition their "hemi" really isnt a hemi either, and the 4.7 doesnt drop valves like the hemi did in the early 2000 models. If it would make you feel better to go through the trouble of selling your truck, then by all means go for it. But be it Dodge, or Ford if you are buying used you run the risk of having problems early on, but you dont need me to tell you that. All models have their own set of problems and they may or may not have to be dealt with during ownership. You already have the truck, why not give it a chance to show you it can take care of you instead of selling it right out of the gate over some internet reviews from people who pay $100 for something and expect it to last a lifetime without any further attention. Good luck with whatever you decide to do.


To the original post, I think it may have been a stuck valve causing your misfire and was freed with the cleaners you used. I just went through basically the same thing on my mom and step dads Aveo, and I so understand and sympathize your frustration. My truck has made that flat tappet noise on startup from day #1 that I bought it, always thought it was a manifold leak. Didnt seem to affect anything so I left it be and have had no issues. I know a lot of 3.7 and 4.7 engines that do this and have done it their whole lives without any negative effects.
 
#6 · (Edited)
lol, dodge's new engines (4.7L included) are very reliable. As they said above, it's all about maintenance. If the oil has been changed, you won't have sludge. The 4.7L is a good engine, very reliable, the worste you could say about it is it makes the tap noise on cold start, but that's usually not an issue. I'd bet your issue is the ecm going bad. I could be wrong but don't see how a valve could cause your issue....it is either electrical or fuel related, and almost certainly electrical...it isn't mechanical, I don't see how a misfire could be something mechanical...

If you buy a ford or toyota, good luck to you, you will need it haha! They are (from my experience) the two most unreliable manufacturers...and the two most overpriced.

Spend an hour a weekend maintaining your vehicles, checking fluids, etc.... and the car will last damn near forever with minimal money invested into them. Don't wait for it to break down, prevent it from happening(it's much cheaper that way and will save a lot of time and headache). I replaced the timing belt on my wife's still running aveo saturday, and everyone asks me "why, it still ran" and I respond with "a $120 timing belt and day's worth of work is a hell of a lot better than a $1,000-$2,000 engine and weekend to put it in..."
 
#7 ·
I replaced the timing belt on my wife's still running aveo saturday, and everyone asks me "why, it still ran" and I respond with "a $120 timing belt and day's worth of work is a hell of a lot better than a $1,000-$2,000 engine and weekend to put it in..."
What year is your wifes Aveo? I spent last week chasing a misfire in my mom and step dads 2005. It ran okay for a few days and then today the CEL and HOLD light flashed again, although the car wasnt misfiring this time. This happened minutes after I changed the oil. Back to the drawing board I guess. This is one car I will be thrilled when they get rid of. Chevrolet puts in their manual to change it every 50k or 60k I forget which one. This particular one let go at 44,xxx, almost out of warranty, taking the valves and head with it. Quality like that might just explain why GM now stands for "Government Motors" lol.
 
#8 ·
What year is your wifes Aveo? I spent last week chasing a misfire in my mom and step dads 2005. It ran okay for a few days and then today the CEL and HOLD light flashed again, although the car wasnt misfiring this time. This happened minutes after I changed the oil. Back to the drawing board I guess. This is one car I will be thrilled when they get rid of. Chevrolet puts in their manual to change it every 50k or 60k I forget which one. This particular one let go at 44,xxx, almost out of warranty, taking the valves and head with it. Quality like that might just explain why GM now stands for "Government Motors" lol.
Ours is a 2004, I believe they are identical. Sorry for your troubles, ours has been literally trouble free until 100,000 miles, then the tstat housing broke and I replaced it for $60. I recommend you replace yours with the autozone metal one if you haven't yet, cheap insurance... We love the car, and yes the timing belt replacement interval is 60k miles unfortunately, but really it's the easiest belt I've ever changed...just need a few extra tools to do it...Also, it is a daewoo engine, so try not to blame GM lol...the new (08 or 09)+ aveos use a GM ecotec engine that is more powerful, more efficient, and more reliable...I like the aveo :)

As for your problem, I'd check plugs, wires, coil, don't know from there....ecm?

Oh any engine codes?
 
#9 ·
Yeah, a P0300 which is multiple cylinder misfire (IMO, actually my first response was "SO SHIIIIITTTT!!!!). It has a new coil, new wires, and new plugs. The lights went off, and everyone was happy except for sputtering which I think is screwy gas. I changed the oil today and the first trip after that the lights came back on. No misfire this time though, nothing abnormal except for the lights blinking for a few minutes and of course the sputter. It may be all tied in, it may not be. I think its something stupid I am overlooking. When I get back to their house I will check all the wires/ connections I may have touched or bumped while changing the oil and see if I can replicate the situation. BTW this has to be the absolute easiest car I have ever changed the oil on.
 
#10 ·
Yeah the car is a dream to work on, even easier than my motorcycles lol!

So after you cleared the codes and now the CEL came on again, is there another code stored?

Hmm I don't really know if it's intermittent, I know it's possible it could be the ecm...but don't know how to check without just replacing it...maybe you could find one cheap on ebay or a junk yard to try that. How many miles on it?
 
#12 ·
Hold on....you said the timing belt broke right? So does that mean you had a new engine installed? If so, they would have had to do a crankshaft sensor variation relearn procedure...and I've heard only the dealer can perform this correctly(~$60). I've read many cases where an engine was swapped in and ran perfect but the light came on and after having this done it was fine. You did say you replaced the engine, yes? And it runs fine right, there's not an actual misfire, just a code?
 
#13 ·
Other causes could be: valve not fully seating, O2 sensor, clogged CAT, Coil, plugs, wires, ECM, crankshaft sensor, camshaft sensor, vacuum leak...

Most likely if it runs fine and you swapped engines it needs the relearn.
 
#14 ·
Hello, first post here :smileup:

I have never owned a Dodge before so hopefully you dodge experts can chime in & point me in the right direction.

I just purchased a 2005 Ram 1500 quad cab with the 4.7 liter engine, I have googled hundreds of websites for answers and it seems that the 4.7 is a less than reliable engine (according to the search results) I hope this isn't true.

When I bought the truck it ran great, passed emissions great and then the next day it started missing, It's cylinder #3 per the OBDII scanner & my own trouble shooting.

I pulled the #3 coil pack plug off & no difference, pulled the #3 injector plug off & no difference, swapped coil packs, injectors, plugs from next cylinder over, no difference, the cylinder is dead, I even swapped injector plugs from adjoining cylinders, still no difference.

I didn't want to spend a bunch of money on parts so swapping the parts from another cylinder will do just as well for trouble shooting.

After reading everything on the web I'm getting worried about a burnt or stuck valve. So I ran a 1/2 pint of SeaFoam through the brake booster hose and shut her down for 5 minutes. Of course on re start I smoked out the neighborhood. I also added 8 oz of Marvel Mystery oil to the oil and hoped it may unstick a valve if it was stuck in the first place.

I took her out on the freeway and really blew her out, the miss starting getting really bad and I got the check engine light again, code P0303 misfire cylinder #3. Then all of a sudden it stopped and started running perfect again.:4-dontknow:

I left the engine running and wiggled everything near #3, injector, coil pack, etc. still ran great. I shut her down & cleared the code & she ran fine the rest of today.

So... My question is what the heck caused it? Was the valve sticking and the Seafoam/Marvel oil freed it up or was it something else? It's got me very nervous now. The engine has 95,xxx on her & I purchased the truck from the original owner who was good friends with a tech at the local Dodge dealer so all maintenance was performed on time. He told me that he never had any trouble & the MIL had never came on before ever.

Could it be carbon build up on the valves? or am I going in the wrong direction? The only other thing I can think of would be the ECU wasn't sending a signal to that one coil pack but that's a long shot.

Also on cold start up you can hear faint tappet sounding noise on the top end for about 1 minute. The Dodge tech said it's completely normal until the oil pressure builds up on the 4.7 liter. Is this common? The oil pressure gauge shoots right up to the normal operating range. I read online that the tapping noise is from carbon build up on the valves, true or false?

Any input is welcome, Thanks Rich
these 4.7 are great engine is that some of us have brought the truck with abuse already but you can't tell until a problem pops up. Like with any engine it's things that could of been provented but previous owners never tried so now we got to fix what we got and make the best of it. I seen many 4.7 go over 180,000 without problems and I have been working on 4.7 for about 6 years now.
My engin
Well I really like the the truck but after reading all of the horror stories about the Dodge engines (all of them) I think it's best to sell it and re coupe my money while I can. It's running great now but there is nothing except negative on the web about Dodge power plants. I guess that's why Ford's & Toyota's hold there value and cost more. I should have done more research before buying it.

Thanks for the good advice, I do appreciate it. I'll know in a couple of weeks if I'll be keeping it or selling it.

Has any of these 4.7 engines went to 150-200k without issues? All I read is about 100k failures, rocker arms, head gaskets, oil sludge, valve seats, etc. It has scared me away from Dodge ownership.
I had to replace my motor couple years ago it had around 180,000 and I was headed out of town with her, not a sound, no knock no lights nothing and boom, she just went dead on me middle of the hIway and I couldn't
figure out why She went dead.My Cousin and I searched for the issue and he saw the metal shaving inthe oil and it was
empty. it locked up out of no where No sound No warning.I got a replacement from a scrap yard and swapped it myself with motor @ about same mileage and sheS doing well en till now and she has missfire on 3 and I'm as
far as the coil pack wasn't the issue and I change all sparks wh.en I swapped motor
 
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