Had posted a thread in regards to my 2001 Jeep GC Limited 4.7 4X4 idling very rough and shutting off. Been doing a lot of diagnosing and still nothing. Compression good in all cylinders, cleaned the TB, replaced the spark plugs, changed out my IAC valve, and still running really rough!!! My spark plugs show that it's running real rich, all came out black(new plugs). Got it up to highway speeds and it runs very smooth. I'm thinking it's a fuel issue cause when it's idling I can smell the excess fumes and at highway speed it runs smooth, I believe cause it's burning off that excess fuel. Need some help on this..... any ideas? Thanks.

 

I would say it's running way too rich. Not so familiar with the 01. What's your fp gauge tell you?

 

Definitely too much fuel, buying a fuel pressure gauge to see how much fuel pressure I'm runnng. Thru all this research I have come accross so many possible issues, it's crazy. Info overload, if indeed there is too much fuel going in, how am I going to diagnose what is causing it?

 

Have to have the basics before you can start guessing, actually, the object is to avoid guessing. Read your FP first then go from there. If your injectors are faulty or the o rings bad, the FP gauge will show the drop in pressure. If we decide the fuel side is ok then start looking elsewhere.

 

if all the plugs are black.. suspect faulty 02 sensor

 

Appreciate the responses, which O2 sensor??? I think I counted 3 in all, 1 on the downpipe and 1 on each of the converters. Faulty O2 sensor would cause it to run rich????

 

NOTHING!!!!! HELP PLEASE!!!!!! LOL! End of my witts

 

How is the new fuel pressure gauge working?