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Wtf is wrong with my tj???

4K views 42 replies 13 participants last post by  _97JeepTJ 
#1 ·
So ive had a weird problem with my jeep lately ill be driving down and all of a sudden the hole vehicle jerks, rpms jump down low, it loses all power, then it goes right back to normal, a minute ago it happened to me and i pulled in the driveway and pulled it out of gear, i sat there a second then the roms went really low ( like 300-400 rpm ) then it went back to about 800 ( idle ) it did that about 3 times then died, i started it back up, moved it then it shut off again. Wtf is wrong?? Bad gas? Fuel pump/filter? At first i thought my clutch was going out but it still did it when it was out of gear and idling. I need to know this is my DD. Thanks in advance.
 
#9 ·
(Don't know if it applies to Jeeps but...)
I had a similar problem with my Grand National. I checked all the grounds, TPS and throttle body. On the GN there's a magnet sensor on the flywheel? When I cleaned it with some sandpaper, no more lunging, jerking other things you are going through. I don't know if Jeeps have those sensors. I'm too new to the Jeep.
 
#10 ·
I checked the throttle body a minute ago and it looked really good and clean and i checked the distributor cap and rotor button and they looked good, ( i also noticed a corroded ground strap ) i also need to clean my battery terminals but im still confused of what is causing the problem, could it be fuel pump, filter, injector??
 
#18 ·
You didn't give the year of your TJ. But, based on the information of erratic RPM's, and dying, I would say to check the cat. It is a known problem with TJ's. In fact, there was a recall for certain years. If the cat is clogged/broken/defective, it would cause the same problems.
 
#27 ·
The cat breaks down inside, so cleaning it will not help. It would need to be replaced. One way to check it is to tap it and listen for a broken glass sound.

I had that problem with my cat. All sorts of irregular RPMs, stalling for no apparent reason. What happens is that the cat collapsed inside, causing an exhaust back up. It would stall my engine. My computer would try to compensate and I would get high RPM's. It was a mess.

I did have an engine check light come on. I didn't notice that you mentioned a engine check light or if you performed a diagnosis. I do remember that there is a way to check for codes. Hope this helps.
 
#26 ·
Ok so it is getting really bad now, i was driving in town earlier and it stalled out going uphill in the middle of the road, it almost did not start back, then i got to a parking lot and it stalled as soon as i parked, if i can find a way to get my fuel pressure tested, what kind of problem would that diagnose? Fuel pump? Because at this point i am convinced that it is the problem
 
#31 ·
Please clean the battery terminals and put some dielectric grease on them, it's just good maintenance, for the love of god PLEASE.

Could be the battery too-new battery, most stores will check it for free. Alternator voltage regulator not charging the battery?-new alternator, also can get it checked. Distributer cap and rotor, clean with sandpaper or replace-check spark too...

Like grim said, could be the crank position sensor, top drivers side on transmission housing to engine-see if the connector is loose...

Start with the battery terminals, and the ground to engine, mine was very bad, had trouble even unbolting it with all the rust.

Just going to have to start cancelling some stuff out by doing it.

If you have to clean some carbon out of your exhaust, like my grandpa always said, 90 mph down the highway will get'rrr done.
 
#34 ·
I would certainly take the advice of those who have replied, but I will say that the symptoms matched mine to a T - especially what you described when climbing a hill. I strongly suspected it was the fuel pump I had just changed (bought it on eBay - last time I do that!). Changed it to an OEM pump and I was back in business.
 
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