[Billycoop127]

I was driving the other day and my jeep starting bucking and jumping. Everytime it did this I dropped speed my RPM would drop and my check engine light would turn on then go off. I sprayed the carb with throttle body cleaner and it stopped jumping and jerking. Now my rpm's
Will go up to 2000 and then down to about 500 while in neutral. Sometimes gradually dropping sometimes just drop sometimes it will go dead. While all this happens my gas gage will show its amount then empty then back up and my check engine light flashes on and off all while I'm
Parked or rolling in neutral can some one help me.

 

[KaiserJeep]

Give us the engine diagnostic codes of the failures, and we may be able to help. If you don't have and cannot borrow a code reader, you might be able to do the ignition key trick and read the codes in the odometer display.

 

[Billycoop127]

Call me uneducated lol but what is the key in the ignition trick

 

[SeVeReDiStOrTiOn]

Remove the throttle body and clean it really good inside and out. Same goes for the IAC valve.

 

[KaiserJeep]

Call me uneducated lol but what is the key in the ignition trick

Put the key in the ignition, and turn to the first click (RUN), then OFF, then RUN, then OFF, then RUN, and stop. This must happen within 10 seconds. Read the failure codes in the odometer display, and write them down. If you turn past RUN by mistake to the second click (START), then turn it off and start over.

This trick works on OBD2 ignitions, but not the original OBD ignitions. I don't know what year it changed.

 

[Phil.Dye]

I had a truck do that before and it was a clogged fuel filter.

 

[CMA_Rider]

I had that problem about a month ago turns out it was a wet clockspring

 

[JPi1]

I was driving the other day and my jeep starting bucking and jumping. Everytime it did this I dropped speed my RPM would drop and my check engine light would turn on then go off. I sprayed the carb with throttle body cleaner and it stopped jumping and jerking. Now my rpm's
Will go up to 2000 and then down to about 500 while in neutral. Sometimes gradually dropping sometimes just drop sometimes it will go dead. While all this happens my gas gage will show its amount then empty then back up and my check engine light flashes on and off all while I'm
Parked or rolling in neutral can some one help me.

Sounds like a ground problem. Somewhere a ground isn't secure and its trying to find ground through the fuel gauge and the ECM. Usually other gauges are affected too.

 

[Patrick H]

This trick works on OBD2 ignitions, but not the original OBD ignitions. I don't know what year it changed.

All TJ's are OBDII. OBDII became standard (mandatory) by 1996. Has nothing to do with which year TJ's had the ability to read codes on the IC

 

[CMA_Rider]

On but dont start it

On, off, on, off, on, off, on and you should get a code if theres a problem

 

[Billycoop127]

Well I tried the ignition switch and it didn't work I did get a code reader but it showed no codes so now I have a " sick jeep" and can't fix it. But. Tom I will try the sea foam engine stuff I put it in my tank first now I put it in the breather in take. I think it a vacuum problem. And other suggestions

 

[Raif]

my jeep did it too. I cleaned the CPS and replaced the VSS. cured!

 

[Phil.Dye]

I still think this sounds like a fuel delivery problem, I would check my filter.

 

[1jeeplvr]

Why not let the Jeep tell you whats wrong instead of guessing? Like mentioned,pull codes.

 

[TJspeed]

I still think this sounds like a fuel delivery problem, I would check my filter.

Our Jeeps have a "non-serviceable" fuel filter.

 

[tallzdatank]

sounds mostly like a problem leading to the fuel pump. not the pump itself but another sensor or bad wire connection.

 

[johnpmcelroy]

Sounds like a ground problem. Somewhere a ground isn't secure and its trying to find ground through the fuel gauge and the ECM. Usually other gauges are affected too.

Thats what I was thinking, he's loosing voltage to the ignition, but the bucking part is unusual?? The bucking part could be clogged fuel injectors or dirty throttle body. I just started a thread about Carb Cleaners versus Fuel Injector cleaner. Did not realize there was a difference.

 

[Billycoop127]

Why not let the Jeep tell you whats wrong instead of guessing? Like mentioned,pull codes.

Well I tried the ignition switch and it didn't work I did get a code reader but it showed no codes so now I have a " sick jeep" and can't fix it. But. Tom I will try the sea foam engine stuff I put it in my tank first now I put it in the breather in take. I think it a vacuum problem. And other suggestions

 

[Billycoop127]

Ok. New update. Did throttle body cleaner. Tried the code reader again. And got no codes to I cleaned out all the vaccine lines. It blew out a lot of whit smoke but still does the samething. I guess I'll start looking for a ground but I have no idea were to even start to look. But now instead of the rpm's dropping to about 500 now it will just go dead sometimes. Could
It be something with the auto choke? I feel
Like its stalling out cause it only shut off if the clutch is in

 

[bmpage84]

All TJ's are OBDII. OBDII became standard (mandatory) by 1996. Has nothing to do with which year TJ's had the ability to read codes on the IC

Although all TJ's are OBDII, obtaining P codes on the IC with the on/off on/off.......etc, will only work on TJ model years 1997, and 2001 thru 2006. No idea why the skipped the years in between.