Bad running Cherokee, can you help me?

I have had a problem with my 2001 Jeep Cherokee when it had it's old engine, and now the same with the new one.

It appears to be getting worse. It will idle badly sometimes and others it will idle fine. It runs good and others it feels like it has lost at least half of it's power and if you floor it it won't move any faster.

If the gas pedal stays in the same position it doesn't get any better. that will last for about 30 seconds to a minute, then it goes away and will run fine. Sometimes it will come to the next stop light or stop sign and will not idle correctly or it will.

I have replaced many things trying to solve this problem over the last year to year and 1/2. I have a new engine, a new spark plug/coil wire setup(what ever it is called),throttle body and sensors, and have dumped a lot of fuel injector cleaner in it also.

do you have an idea what I could do, or what is wrong with my Jeep? I have spent a lot on this Jeep trying to restore it to 100% and I want it to run like it did before. Thanks for the help and thought you may have given my problem.

What about your Cats? Mine ran like poo when the cat failed but sometimes it worked good because the crap inside would flop around amd clear the pipe for the exhaust to clear out. I found out mine was bad because it was running bad and I dropped my lighter so I had to reach under it and seen the cat Glowing Red like holy crap.

Have you replaced your o2 sensors? Mine was doing the same thing and replacing both o2 sensors fixed it.

have you checked for codes?

Hooked it up to a scanner and looked at fuel trims/sensor inputs?

I have replaced both O2 sensors, and it is showing no codes.

You need to get it somewhere that you can read the sensor inputs.

As you've found out, throwing parts at it doesn't work to well.

You need to see what the PCM is seeing so you can track down the sensor that's feeding bad information, or eliminate the sensors as an issue and start looking for mechanical problems.

I had the same problem with my 2000. In your original post, you don't make it clear if you replaced your coilpack. the reason I mention that is because that is precisely what was wrong with mine. It had an inconsistant lose of power either at idle or at speed. I was looking under the hood one day when it was acting up & could see the first plug wire in the coilpack arcing against the head. New coilpack & the problem went away.