[supernova1021]

Bear with me. I'm no mechanic and have posted this before. 2001 4.0 auto sahara 122k miles. Bought it about two months ago and dealer said he would fix anything wrong with it. Too bad for him. Lol. Shortly after I bought the jeep it would randomly die while driving. No warning no nothing. And was very hard to start. Sometimes up to 30 min before it would start. Was showing a crankshaft position sensor code. Jeep dealership replaced the cps and computer all on his dime.

Got it back and when driving on the interstate around 70 and it is up to temp it starts bucking and missing and cel light comes on. Now it is showing codes 300 302 all the way to 306. Random misfire... Can pull over and redstart and all is good until back around 70 or so, does it all over again.

Cat was tested and is fine. New coil rail, plugs (first champion double platinum and now champion truck plugs and they looked fine) and tps were put on. Battery and alternator tested fine and terminals are CLEAN. Voltage does not drop when it misfires. New mechanic yesterday put on a new fuel pump since he "determined" it was bad and sucking air in with the fuel. Drove it today and same thing...70 to 75mph started bucking, lost power and codes said random misfire all the way to the #6 cylinder.

Sorry for the long post but I'm lost and don't have any faith in mechanics around here anymore. Maybe a burned wire, bad ground, injector?? Weird how it does it at around 70 and I can kill it and it's fine until driving around 70mph again. It's fine running around town...

 

[robbiecc]

bright side-it ain't your dime and for a 10 yr old vehicle gettin fixed for free from a dealer-you definatly got the better end. is there a time limit that he'll keep fixing things?
all i got was the 'whistle warentee' dealer started whistling while i pulled away-as long as i could hear him, it was covered

 

[SurfnSnow]

That's weird and sucks that it's happening. I had the same thing, missfire, bucking and loss of power while driving on the highway. The dealership changed the exact same items that you have had changed and it's been a-ok. You could have a bad ground and so that'd be worth checking out.

 

[benamin]

Don't know if it will help but i had a similar issue years back with my jeep bucking and having issues that turned out to be a stuck lifter it subsequently ate my cam alive hence why now I run a stroker motor

 

[supernova1021]

Man, I don't know anymore. And yes, I am VERY fortunate the place I bought it from is paying for it. And I am sure the guy is reaching his limit. He has spent a lot of cash on it.

 

[distortedtj]

Has the dealer looked at the "TSB" out for cam gears.

 

[supernova1021]

Has the dealer looked at the "TSB" out for cam gears.

No idea. But I'll find out.

 

[kiko525sx]

sorry about my english,but I hade the same problem years ago,diferent jeep ok!
a very small whats the name....ahhh f..k ....in the fuel line
miss the word danm..
check the fuel line and fuel filter but fuel line small (holle?) letting the air in when the engine starts to charge
sorry but I hope you understand

 

[supernova1021]

I know what you're saying.. A hole letting air in. That's what the last mechanic said and said he had fixed it. Problem remains. He told me the fuel pressure tested out at 40 before he fixed the problem and said that was on the low side. I think 40 is pretty good is it not??

 

[Ageless Stranger]

I know what you're saying.. A hole letting air in. That's what the last mechanic said and said he had fixed it. Problem remains. He told me the fuel pressure tested out at 40 before he fixed the problem and said that was on the low side. I think 40 is pretty good is it not??

Spec is 49 +/- 5psi.

 

[supernova1021]

Ahh.. Ok. I tried searching here but could not find the spec this morning. Well, new fuel pump didn't fix it so back to the shop it goes..

 

[Jeepfreak83]

I would have to day check the crankshaft position sensor easy test and it will make the jeep misfire and throw codes let me know if u need help finding out how to do this test .

 

[mrcarcrazy]

Wanna trade? I have an 01 with the 5spd. My complaint is the transmission...its a POS.

I want an Auto...

 

[supernova1021]

I would have to day check the crankshaft position sensor easy test and it will make the jeep misfire and throw codes let me know if u need help finding out how to do this test .

Thought about that sensor too. How does one test it? And thx..

 

[supernova1021]

Stopped by the mechanics last night and spoke with him. I had said in prior posts that the camshaft position sensor had been changed. Well, it hasn't and he swears that is the problem. A new one is on the way and I guess I'll find out when he puts it on. Dealer told me two months ago that it had been changed....

 

[mrcarcrazy]

good luck.

 

[tylerlepage]

sounds like you need a new mechanic? did you replace the sensor after it threw the code or did it clear out fine

 

[supernova1021]

sounds like you need a new mechanic? did you replace the sensor after it threw the code or did it clear out fine

LOL. Yeah, tell me about it. This makes the FOURTH mechanic the dealer has sent it to (including the Jeep dealership). It began by showing codes for both the crankshaft and camshaft position sensors. First mechanic replaced the crankshaft position sensor but not the camshaft.. I was then told that BOTH were replaced. Same codes continued and Jeep dealer put on a new computer. CPS codes went away and I now get random misfire codes. I then replaced the plugs twice, new coil rail and then TPS. Last mechanic replaced the fuel pump after it showed low fuel pressure and he found something worn inside the pump (I was told it was a hose inside)...

New mechanic swears it to be a camshaft position sensor, so we will see. He told me last night that after replacing it, the new sensor has to be "timed" or something like that. I searched for instructions on the procedure for replacing it and could not find anything about "timing" it.

 

[supernova1021]

Picked up the jeep with the new camshaft position sensor last night. While driving 10 miles to work this morning on the interstate the same old thing... CEL flashing, bucking, loss of power. Same codes..

I'm done with it.

 

[Jeepfreak83]

Man check the timing. sounds like u are fed up look I had problems with mine and I ended up replacing camshaft sensor and crankshaft sensor they work together if the distributor was ever pulled this motor (4.0) is very picky have to follow oem specs when putting distributor back in sounds like u don't do your own work so u don't know where the other pep hands have been. All electrical parts should be tested and make sure they are good before install. One thing I noticed when I replaced my distributor is it's the same for the 2.5 and 4.0 u just have to set it to what motor u have and they don't come set look at oem specs says use Allen key to keep gears lined up. I am a mechanic and I have the shop manual on the tj it's got all the part numbers and instructions it's like 1500 pages i have it on disk. Send me a pm if u are interested.