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Discussion Starter · #1 ·
I've searched and i couldn't find, so i decided to stop lurking and join this fine community....

my 2002 Ram 1500 4.7L has decided to give me this strange stutter/hesitation/sluggish feeling when driving around 45-50mph...

once i'm doing that speed, if i let off the gas and apply just a slight amount of throttle to maintain, it will shake like it's choking for fuel....if i give it more gas it will fire right up and carry on....it only happens at 45-50 and only when i give it a little gas (1500-1800rpms)

when i do apply the slight throttle, the RPM's rise up to about 2000, and then drop suddenly to 1500 and the truck starts stuttering/choking....

i've changed the TPS/plugs/IAC...i was going to change the MAP sensor (worst location for a sensor EVER IMHO) but rock auto sent me the wrong part...so back to troubleshooting my issue....today i am going to check fuel pressure, both at idle and under load...i've read that it is 50psi...

has anyone solved this weird throttle stutter issue at these speeds? again, i did search, but could not find an actual answer to the problem....

also, i recently had all fluids flushed and changed out (minus the radiator cause that's expensive and i needed to buy sensors!) ran a fuel system cleaner (jiffy lube special stuff) and a can of Seafoam through the gas

i do NOT drive it like i stole it, i've taken it on the highway to blow it out, but the CEL flashes at me so i slow down....if i get on it, the CEL flashes at me, but doesn't throw a code..i keep my code reader in the car JIC i can catch a code thrown!
 

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Check your upstream O2 sensors. When they go bad they send bad signals to the PCU and it can cause all kinds of weird running issues. If they are old, I'd change them out and see if that helps. Use OEM ones.
 

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Hey Thedonk13,
I'm not sure that this has any real weight, but this sounds exactly like what my '02 4.7 did, almost to the T, when I was having a cylinder misfire on my 8th cylinder. It dropped a rocker arm (which isn't common, but not unknown for the 4.7). It sounds like you're doing your maintenance, so that's great.

I had a huge sludge issue when I bought the vehicle, and a lack of initial oil pressure caused a lifter to collapse, allowing the rocker arm to fall off. It's weird that it's not throwing a code, but maybe check your compression on your cylinders?

Good luck, and here's to many more Dodge miles!
 

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Discussion Starter · #4 ·
i forgot to add i think...i'm only getting 7.7mpg around town! according the comp...literally, only got 180 miles before the fuel light came on so i "know" i gotta be running super rich, but my fuel doesn't smell gassy...

i will do the o2 sensors next...really hoping that works, don't want to throw it at a mechanic who will misdiag things and convince me to rebuild my tranny only for it to have the same problems....

it's not shifting weird, or acting up at all....my throttle body is nasty as hell, so i'm going to be cleaning that bad boy next weekend (gotta play soldier this weekend)...when i pulled out my IAC, it was coated in carbon and "sludge"...

i was throwing misfire errors, but i swapped around my coils and it hasn't threw a bad one yet, i think my #2 coil wasn't seated properly or something, because it's been a week since i swapped them and it hasn't thrown an error yet....

trying to stay on top of anything since its got 165K on the thing...
 

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Keep us posted on what you find out, would like to know what ended up being your problem, I swear my truck (which has ~169K miles on it) was doing the same thing. The first time I was getting about 11.2 mpg, after some work on the misfires and oil, it came up to 14.5 mpg, and now it seems to be improving even more. I calculate my mileage by hand.

Like I said, please keep us posted!
Good luck.
 

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Discussion Starter · #6 ·
So i checked my fuel pressure, sits around 45-50PSI in idle...give it gas and hold it, locks pretty solid at 45PSI....

i think this is good from what i've read.....still buggered a bit...

yesterday, gave it some gas going home and it was crawling after 3500RPMs...wouldn't go much faster than that...than the CEL started blinking..

really want rock auto to give me my store credit so i can get my o2 sensors on the way...
 

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Discussion Starter · #7 ·
so after i got my new 02 sensor in place and reset the PCM, my fuel mileage went up to 9.5 (according to the display)...but the shaking was present....

after scratching my head and searching my heart away, i gave in and asked for a good mechanic to diagnose my issue...a couple hundred bucks later (im in the wrong business) and he informed me i'm losing 20% compression in the engine!

so lame....time to debate on rebuild vs new engine.....leaning towards new engine but we will see
 

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Hey man, that really blows. &That's a lot of money for a diagnosis. yeouch...

You might be able to find a decent used 4.7L engine at a junk/scrap yard for a lot less, if you want to try something like that. I know my local salvage yard offers a 30 return policy... maybe something to look at. Just a thought.

Another thing, not to beat a dead horse, but if you're really gonna replace the engine, pull the valve covers. Check out what's going on there. JMHO

Or maybe I'm not understanding what the mechanic told you-- wouldn't be the first time I had a major blonde moment :LOL:

I'm really sorry about your luck.

Keep us posted on what you decide, Thedonk13!
 

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I've searched and i couldn't find, so i decided to stop lurking and join this fine community....

my 2002 Ram 1500 4.7L has decided to give me this strange stutter/hesitation/sluggish feeling when driving around 45-50mph...

once i'm doing that speed, if i let off the gas and apply just a slight amount of throttle to maintain, it will shake like it's choking for fuel....if i give it more gas it will fire right up and carry on....it only happens at 45-50 and only when i give it a little gas (1500-1800rpms)

when i do apply the slight throttle, the RPM's rise up to about 2000, and then drop suddenly to 1500 and the truck starts stuttering/choking....

i've changed the TPS/plugs/IAC...i was going to change the MAP sensor (worst location for a sensor EVER IMHO) but rock auto sent me the wrong part...so back to troubleshooting my issue....today i am going to check fuel pressure, both at idle and under load...i've read that it is 50psi...

has anyone solved this weird throttle stutter issue at these speeds? again, i did search, but could not find an actual answer to the problem....

also, i recently had all fluids flushed and changed out (minus the radiator cause that's expensive and i needed to buy sensors!) ran a fuel system cleaner (jiffy lube special stuff) and a can of Seafoam through the gas

i do NOT drive it like i stole it, i've taken it on the highway to blow it out, but the CEL flashes at me so i slow down....if i get on it, the CEL flashes at me, but doesn't throw a code..i keep my code reader in the car JIC i can catch a code thrown!


Have you tried replacing the EGR valve? Just disconnect it and if the problem goes away then its a bad valve. $50 at NAPA, autozone, etc. LIke 3 bolts and some wires. 20 minutes on my 4.7l.
 
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