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If you can solve this problem you are a genious

7K views 29 replies 15 participants last post by  Moparite 
#1 ·
99Ram 2500 v10
This is the scenario:
I start the truck and let it idle for 20 seconds, drive 4 blocks through town then down the highway. I get almost 2 miles down the highway and suddenly the truck looses power, starts to miss and may even try to backfire through the intake. If I accelerate nothing happens until the foot pedal is on the floor then suddenly the truck takes off like a rocket but still running rough. It will do this for about 1 minute then clear up and run great. I sometimes pull over and let it idle out of the problem.

It happens every day, the exact same place on the highway. If I let the truck idle in my driveway after about 3 minutes it will idle rough for about 2 minutes.

If I drive a distance and shut the truck off for a few minutes the whole cycle happens again.

New intake air temp sensor, MAP sensor and had the computer tested by Cardone, they found no issues but flashed and sent back.

I am at wits end with this.
 
#2 ·
Check the fuel filter? How's the fuel pump?
 
#4 ·
How many miles is on the truck?
 
#6 ·
Truck has 98000 miles and the fuel pump was replaced because it would not start one day. I hit the tank with a rubber hammer and the pump kicked in, I replaced the pump the next day.

I double checked the fuel pressure tonight and it is 50psi. There is no way it's the fuel pump, they either work or they don't and this one has good pressure.

Also, my truck has had this problem for 3 years! I drive the truck so little I have never really worried about it but now I want to get it fixed.

A little history on the truck:
I bought it in 2001 with 50000 miles. It has 36" BFG mud terrains, ARB air lockers front and rear, throttle body spacer and 3" lift. 5 years ago I broke off a rocker arm stud and then had the heads rebuilt. 4 years ago I lost oil pressure while driving. Shop took the pan off and found sludge in the pan. They cleaned the motor and it was good to go. 3 years ago while pulling the boat off the lake the truck acted up for the first time and it has done it ever since.
 
#25 ·
Truck has 98000 miles and the fuel pump was replaced because it would not start one day. I hit the tank with a rubber hammer and the pump kicked in, I replaced the pump the next day.

I double checked the fuel pressure tonight and it is 50psi. There is no way it's the fuel pump, they either work or they don't and this one has good pressure.

Also, my truck has had this problem for 3 years! I drive the truck so little I have never really worried about it but now I want to get it fixed.

A little history on the truck:
I bought it in 2001 with 50000 miles. It has 36" BFG mud terrains, ARB air lockers front and rear, throttle body spacer and 3" lift. 5 years ago I broke off a rocker arm stud and then had the heads rebuilt. 4 years ago I lost oil pressure while driving. Shop took the pan off and found sludge in the pan. They cleaned the motor and it was good to go. 3 years ago while pulling the boat off the lake the truck acted up for the first time and it has done it ever since.
V10 wer noted to have a warped intake manifold and leak bet you take it off place gaskets clean all ports including egr which be partially pulled..then proceed look for tub for you vehicle
 
#9 ·
^^^^check the cats^^^^
 
#10 ·
I don't mean to sound like a dick but you need to start at the beginning...

Do you have any check engine lights? If so, what are the code(s)?

It seems like you may have an issue with one or more sensors or the computer.

When you start the truck it is in cold start fuel enrichment open loop mode. At this time it ignores many of the sensors and uses predetermined fuel and timing maps. Once warmed up it enters closed loop mode where it takes input from all the sensors. It sounds like you are having an issue at this transition.

You also mentioned it runs great at WOT(wide open throttle). This also falls in line with the above comment. When at WOT the computer enters another open loop mode, usually referred to as WOT open loop mode. Again, ignoring many sensors and using predetermined fuel and timing maps.

Without any other information, and if I had to take a stab at it I'd replace the upstream(closest to the engine) O2 sensors. Don't waste time with the downstream(post catalytic converter) sensors, they are purely for emissions and nothing else.

I'm not real familiar with the v10, what sensors it has(MAF vs MAP, etc). If you have a CEL that will tell all...
 
#12 ·
I believe the reason it's the same spot every time is because it's when the truck switches from open loop to closed loop like I explained above. Doesn't matter where you drive, it will still do it. There are several constraints, one is time. The vehicle will stay in open loop for X amount of seconds upon start up. The other main constraint is coolant temperature.
 
#13 ·
Ya what he said^^^^ and does the v10 have 4cats?
 
#15 ·
The truck has 2 cats. I just took a look and only see 2, O2 sensors in front of the cats, nothing behind them. The cats do have a rattle but I would assume that would only affect power and I cannot imagine they would cause a problem like I am having.

I have checked codes in the past, not exactly sure what they were exactly but the codes were injector misfire codes and it was a different cylinder every time.

What is a CEL?

Truck has a MAP sensor which I just replaced, no MAF sensor
 
#16 ·
CEL is check engine light. Get autozone or some other shop to scan the codes(they do it free). Write the codes down and post them here. You could have a bad pcm if it's a random misfire.

Does that engine have an individual coil for each cylinder? Or does it have a distributor?

The code(s) will give the info needed to diagnose the issue. Don't let the parts guy at the counter tell you his diagnosis, they are usually wrong. Just write down the actual codes and post them here. I'd be very surprised if there were no post cat O2 sensors on a 1999...actually, that's OBD2 so I"m pretty sure it has to have them.
 
#18 ·
I believe there are two more 02 sensors forward of the two you see by the cats. Those are the rear sensors.
I agree the CEL will tell the story. If you have cats rattling then you have BAD cats. Bad cats can cause interesting problems. If there rattling they are loose inside & could slide to a place of possible particle blockage at times.
 
#21 ·
Took the truck to O Riley's and they checked for codes and found none. They looked up O2 sensors and said there are many options. Could have either 2 or 4. I went to Napa where I know and trust most of the guys that work there. They only listed 4 O2 sensors for a 99'.

I bought the front 2, closest to the exhaust manifolds and went home to install them. I then found 2 other connections above the transmission for additional sensors but my truck only has 2. I called an older mechanic I know and he said if my truck were an early build 99' it may only have 2 because he thinks 98' only has 2. This could be why when I looked into replacing the computer I found there were 3 different ones and no one was able to order the one I needed, it was rebuild only.

I installed both sensors on Saturday and after 3 short trips so far everything is working great.

I talked with our trainer at work Friday(I am a forklift mechanic) and he said if my O2 sensors are 4 wire they are more than Likely heated sensors and that could be why it runs like crap in closed loop until they get to correct operating temp.

I want to thank everyone for all the help and I will update this in a couple of days to let you know if everything is ok.
 
#24 ·
Reading DCT's on 1998 and newer ram

Glad its fixed.
Future reference thought you might be interested. DCT Reads out on digital odometer screen in our trucks. DCT= Diagnostic Trouble Code
Sounds to me like it was intermittent issue. Unless its running bad when code reader used it may not store that code long enough to read it. You have "hard code" it stores until erased with a code reader, and "soft codes" will clear them selves if problem stops. Normally in so many start cycles like 3. Each manufacture does a little different programming specific to them. If you have an intermittent issue pull over and attempt to get code while its running badly if you can.

1998 and Newer Model Rams

Turn the ignition on while pushing the odometer clearing button simultaneously. Engine codes will read on models with digital odometers. This feature also tests all dash panels.

JP :smileup:




http://www.ehow.com/how_6911170_check-engine-codes-dodge-ram.html#ixzz2SwDZXeL0
 
#27 ·
I actually had exactly the same thing with my BMW 540i. And no error code.
After a while being tired of it, I started checking- and I found, there was a gasket under the intake boot to the throttle body was cracked. I replaced it with what I had- a rubber band from the newspaper, put some garage door grease (it actually does not destroy rubber) on it for the boot to slide over and put the clamp on. It never happened again.
Long story short- check for air leaks.
 
#28 ·
I actually had exactly the same thing with my BMW 540i. And no error code.
After a while being tired of it, I started checking- and I found, there was a gasket under the intake boot to the throttle body was cracked. I replaced it with what I had- a rubber band from the newspaper, put some garage door grease (it actually does not destroy rubber) on it for the boot to slide over and put the clamp on. It never happened again.
Long story short- check for air leaks.
[/Read the op. EIGHT YEARS AGO THIS MEANT SOMETHING
 
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