I just bought a 1995 dodge ram 2500 with s 5.9l magnum. It had a blown trans which I rebuilt. I got it running and driving and new exhaust. After it runs for awhile it likes to act up. It will drop in rpm's and eventually die if your not constantly giving it gas. I've read the codes on it and it says nothing. I've unplugged the o2 sensor and still no change in behavior of course this will give a code. Fuel pressure is around 45 and doesnt change when the truck likes act up. Another problem it has is it like to smoke in the through the vents. I would like to fix these problems so I can get it back on the road. Please and Thanks

 

Smoke in thru the vents is likely a bad heater core. Those are fun......

Think I would start with a VERY thorough cleaning of the throttle body. Take it off, clean it REALLY well, paying special attention to the IAC well..... (don't dink with the IAC motor itself though. You can wipe off the end of the pintle, but, don't turn it.....) Leave the battery disconnected while cleaning. (new gasket is only like 3 bucks....) when you have it reinstalled, squeaky clean, hook the battery back up, turn the ignition to On, (not start) count to ten, (don't touch anything) THEN start the truck. It should figure out idle fairly quickly. (assuming nothing else is bad. )

 

It runs and idles fine at first but after some time of driving it then starts to act up. You can shut off and back on again and it will idle fine but once you put it in gear it starts doing it again

 

Still points to the throttle body IAC. Give that throttle body a good cleaning. You can take a look at this post for the process (https://dodgeforum.com/forum/2nd-gen...le-body-4.html) or check out the many videos on YouTube.

 

Usually, that's an O2 sensor... but, you have already tried that test..... You have only one sensor? Correct??

How long does it run before it screws up? Have you tried resetting the PCM? (disconnect battery, turn on headlights, turn off headlights, reconnect battery, turn ignition On (not start), count to 10, don't touch anything..... then start the truck. Should figure out idle pretty quick.

 

Yes only one o2 sensor
it will idle forever its when it start to be driven that after awhile it starts. Sorry if i didnt make that clear the first time

 

pcm restart didn't change anything

 

Gonna need a scanner that can do data logging to see what is changing that the engine doesn't wanna stay running......