I have a 2002 Grand Cherokee that has an issue that is driving me nuts. Long story short, if I let off the gas and coast for more than 5-10 seconds it goes into limp mode. The interesting part is that it drives fine once there is less than 1/4 tank of gas.

It returns multiple misfire in 3 and 6 as well as multiple misfires.

I have replaced the 3 and 6 injectors, replaced the plugs and boots, replaced the coil pack, replaced the fuel filter, replaced the o2 sensors and ran Mopar ccc and fuel additives through it.

Any suggestions where to look next? The difference between how it runs between empty and 1/4 vs how it runs between 1/4 and full really has me stumped.

Thanks guys!

 

Welcome to CF!

Well this really has me pondering also. My computer monitor faded to black twice now, but I still don't have a clue! Bummer!

Nope! Sorry! I'll keep thinking.

 

Okay, here goes a wild guess! Under the fuel tank shield, there are straps that secure the fuel tank to the body. If those straps are broken, the tank rests on the shield and may be pinching/stretching the fuel lines when it's full.

If that's the cause, please let us know.

 

Holy crap... just went and checked, and there is a loose strap and the tank is laying directly on the shield. After I repair it, I will let you know the results.
Thanks!

 

BINGO!!! It's amazing what you think about when you try! I almost burnt out my brain thinking about that one.

I don't think you'll have to worry about the fuel pump because if I remember correctly, they have an internal pressure relief at 100 psi in case they get blocked.

 

I would have never thought of that - amazing!

 

Well, maybe it's my analytical brain. My parents thought I was autistic before they knew what that was. I always had a flare for science and physics.

 

Dave. You are truly amazing..

 

I am probably doing this wrong, so apologies in advance. I am a Newbie to posting questions here but I read a lot and have found many answers to Jeep Cherokee questions. I own a 99 4.0 Cherokee as my DD and have a 2000 Jeep Wrangler. I have purchased a 2002 GC Limited with the 4.7 non HO V8. The valve seat had dropped out on 4 cylinders. I will have to purchase new heads. I have had the block examined and all is good. I plan on purchasing the DNJ rebuild kit that includes the piston replacement and the timing chain full replacement. The intake manifold was also damaged. The back of the manifold is missing and I am trying to find a replacement. I have looked on Ebay and other salvage yards. There are manifolds to be found. I am told that a 2001 and a 2002 are the only manifolds that will work for my application. I am more interested in the exact part numbers that will fit my application. Many of the replacements I have found only list part numbers and I am not sure which ones are interchangeable.

As I stated, I am new to posting questions and I did not find the answer to my question in other threads. Is anyone familiar with the part numbers or can tell we somewhere I may look.

Thanks in advance for any responses.

 

On craigslist for Tulsa, OK. there is a engine rebuilder that has nothing but Jeep engines lots of 4.0' 4.7, 4.7HO's for sale very reasonable. Look up their listing online and give them a call, I'm in SW,MO. and have saw it many times because of the listed 4.7's.

 

Fred,

Do you have any experience with DNJ rebuild kits or any other products manufactured under that name?