i have a 2002 ram 2500 4wd 5.9l V8 gas. when i start it on a cold morning it misses, bucks and cuts out. The colder the morning, the worse it runs. Once it gets to normal running temp. it runs great. i have checked or replaced: O2 sensors, Manifold temp sensor, Collant temp sensor, MAP sensor, Fuel pump pressure. I even tried a different PCM, no luck. The truck has 215,000 miles on it. any ideas?

 

Is the truck setting ay dtc codes? that will clue you (or us) as to where to start looking rather than throwing parts at it. When you say "cold morning" what does that mean? I live in northern Indiana, 15 degf is not uncommon.

 

I know i have an injector going out and on cold mornings (below 50F here in dallas) It will rough idle meaning it will peak up to 1k and drop to 500 rpm at idle while driving or after few mins of warm up all is fine.

 

Seeing how it runs fine when the weather is warm or the car is warmed up, it may just be moisture in the fuel. Cold weather is a bit tougher on cars, especially when starting them after they have sat for hours.

Have you tried adding a bit of HEET to your fuel?

http://auto.howstuffworks.com/car-dr...-in-winter.htm

 

I had trouble this winter on cold mornings. It was the spark plug wires.

 

Thanks for the info guys
- i get codes for crank/cam position sensor. both have been replaced.
- i have also gotten codes for mutiple mis-fire (didn't need a computer to tell me that) and primary coil. all have been replaced.
- i thought about contaminated fuel, tried HEET, no luck so i removed the gas tank to check the screen and empty the tank. i also blew out the fuel lines incase any water was in a low spot and freezing.
-i first noticed the problem last fall when the temp droped below 40dF. this winter in Cincinnati OH has been cold. on days in the teens the problem doesn't change it just taks longer to start runnig OK.
- i ran a scan while the engin was cold and than again while the engin was warm. i believe these are "point in time" sensor readings. Noticable differences were; Ing Advance..32.5d cold and 21d warm (this seems backward to me), there were differences in the ST FTRM1, LT FTRM1, and the ST FTRM11. (can any one tell me what these are reading?)

 

ST and LT FTRM are short term and long term fuel trim. Best case scenario they should be 0 (+/- 10 is ok). If they are positive it means it's trying to compensate for being too lean, negative it's trying to compensate for being too rich. Vacuum leak maybe? Plenum gasket?