I have a 1995 Dodge Ram 1500 5.2L V8 with a manual transmission (82k miles) that has an idle problem.

When I first start it, it will idle fine for a minute or two then it will begin to stutter and idle rough, and sometimes almost die. It hasn't died on me yet though. It will do this for about a minute before it quits, and rarely, it will do it a second time if I let it keep idling. I can smell gas when it does this. If I don't let it idle that long and just drive, it will run rough, jerk, and backfire (out the carb I think) until the "coughing spell" passes.

I purchased a Haynes Repair Manual and looked through that a bit for troubleshooting. I have replaced the PCV valve which seemed slightly sluggish, and cleaned out the Crankcase inlet filter. There are also no codes that appear when I cycle the key on-off-on-off-on. I have read on this forum that the IAC is prone to buildup and fouling on these trucks but I haven't attempted to clean it yet. I am a mechanic, but not an AUTO mechanic and am not familiar with engines. So I've been a little hesitant to attempt it.

This problem started a couple of years ago, about two weeks after installing a Spectre cold air intake (I don't know if I still have the OEM intake). I'm not sure if I should have reset the computer or not after installing it. I had a tune-up at about 75k miles that didn't fix the problem. It's really starting to bug me. Any suggestions?

 

All the signs of a failing pre-cat O2 sensor.

 

This is EXACTLY the same issue I am having.

Heyyou here has helped me out with it alot, he also suggested a new Pre-cat O2 for me as well, though I havent had the $$$ to replace it yet.

I have replaced the plenum, IAC, plugs, wires, NOTHING helped the issue at all. I first tried cleaning my IAC, didnt help, I bought a brand new one, still absolutely no change.

If you do change your O2 and it fixes the problem PLEASE message me and let me know if it works.

Thanks!

 

Is there a quick way to test this?

 

I haven't had a chance to try this yet because its been raining cats and dogs here, but if you unplug the o2 sensor from the wiring harness then start it up and let it run to the point where it normally starts to choke and see if anything different happens.

This will produce a CEL, just unhook your negative battery terminal after for 30 seconds to clear the code.

Dont attempt to clean an O2 sensor, you WILL wreck it.

 

I'll give that a try, thanks!

 

One thing that hasn't been mentioned here is check your ECT sensor. I had those similar symptoms with start up. I did not have a check engine light on either. Replaced alot of things until I got frustrated took it to a shop and they found the ect was bad. Sometimes its just the last thing you expect to be wrong.

 

What is ect ?

 

Engine coolant temp.

 

Ok. I disconnected the sensor and had no rough idle. I also didn't get a check engine light or a code though. (Is that weird?) When I reconnected it, it idled rough again.