2001 Ram 1500 3.9 stalling/dying

Nonya0992

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Location
Kansas
Ram Year
2001
Engine
3.9
Help Please!!!

2001 Ram 1500 with 3.9 v6. After 5 minutes of driving from cold start it starts to stutter, backfire, and tries to die. This lasts for maybe 30 seconds to 2 minutes. Then wont do it again until it cools down again for another cold start. What am I missing?

My notes:
-200k miles.
-New coil, cap/rotor, ignition pickup sensor, plugs, wires.
-New fuel pump and filter.
-Maintains 48psi fuel pressure while running and then stuttering.
-Unplugging the MAP makes no change.
-Scanner shows O2 is working well, but looks sluggish. (could be that its OBD1)
-LTFT is floored between -22 and -33 while at idle and soft throttle. Levels out to about 0 when at half to WOT.
-IAT appears to be working fine.
-Ignition advance bounces all over the place during idle.
-Idles rough. Check engine light is currently on but there are no trouble codes. There was cylinder missfire previously.
 

scrounge

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Deep in the heart of Texas
Ram Year
1999
Engine
318
The IAC motor (or sensor) on the back of the throttle body, and the cavity where it resides, might need cleaning, which will be more complete if you take off the throttle body and clean the entire unit. No guarantees that this will work, but it's the first place I'd address, and it'll be cheaper than throwing parts at the problem.

You'll need an OBDII scanner to read the codes on this truck. And if the CEL isn't on, it won't be much, if any, help.
 

crazy jerry

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6.4
not sure if its the same but i had 96 with 3.9 that ran great. a while after i sold it the owner contacted me because it was either running rough or stalling. i told him to check the iac as i figured that was likely the problem. i believe he replaced it and it ran good after
 

Nonya0992

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Location
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Ram Year
2001
Engine
3.9
Update: Solved the issue. I still have a tough idle but thedying issue has been resolved. The problem was a faulty crankshaft position sensor. Im not sure why it needs a CPS for an engine that has a full distributor. But it doesnt die anymore and its more peppy with a lot more power too.
 
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