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.

 

You sir, need to replace your fuel pump.

 

When its running poorly check for proper fuel pressure and good spark.

It could be that you got a bad TPS or something right outbof the box.

 

When its running poorly check for proper fuel pressure and good spark.

It could be that you got a bad TPS or something right outbof the box.

 

Might want to have your O2 sensors checked with a scan tool.

The computer may be storing fault codes for that or other things. Diagnose before throwing parts at it.

 

One suggestion my mechanics friends have said to me is to take it to a mechanic, let them diagnose it then fix it yourself. That's what I've done. Two more things left and mine will be up to par. Just my two cents.

 

I have new O2 sensors in it now.
I am going to have the fuel pressure checked.
My friend and I are working on this together, he IS a mechanic

 

I would at least confirm its bad before just throwing parts at it...

 

I know it has been a long time since I have posted on here but, my Jeep is now fixed and is running great again! There were some small problems with the jeep such as the motor mounts, that I was told were brand new were not, needed to be replaced.

The bad motor mounts allowed the engine, which you could not feel, shake bad enough that it effected the knock sensor. The sensor tryed to adjust the engine and that caused a problem.

We replaced the motor mounts thinking it would fix the problem, it did not.

There were several other small problems that gave us "a big problem" that we fixed.We replaced every sensor you can think of, wow the cost! Even after we got all of the small things fixed, which could be wrong with your jeep and not cause anything, it still ran like shxt. We had been working with a dealership and one of the "tecs" said he wanted a look at it. The first thing he asked was "have you timed the new engine since you have put it in?" My mechanic friend said " yes of course I did". The Tec then asked if he used a computer, and my friend did not. The next thing he said, and did, floored us both. The tec told us that my jeep, 2001 Jeep Cherokee, has to be timed with a computer. All other Jeep Cherokees older than mine, 2000 and back didn't need to be timed on a computer. We both thought this guy was full of shxt! We gave him the keys, and after being on the computer for 2 days, it runs like a brand new Jeep!! He put it through all types of test to include a warm start and a cold one. It runs great! He told me that very few people, the do an engine swap, will tell you that it needs to be timed on a computer. He did tell me that mine was 30 degrees out of time. I was amazed that it even ran!!

I just thought that I would pass this along to all of you just in case you may be having problems that you can not figure out.

 

Moral of the story:

Don't throw parts at a problem. Diagnose first.

 

very very true! Same thing my mechanic say, now!!