Collector grade Jeep Wrangler TJs for sale

Jeep bucking and jerking on acceleration

Axl98

Axl98

Member
Original poster
Joined
Nov 2, 2021
Messages
35
Location
Florida
98 TJ with 147k miles , while accelerating it’s started bucking and jerking and hesitating.
Sounds like the fuel isn’t getting to the engine right

Could it be a clogged fuel filter ( which is inside the fuel pump)
No CEL, shifts fine (it’s a manual)
Thank you
 
Could be your throttle body acting up. Unrelated, but I had these same kinds of symptoms in my daily recently and the culprit was a bad TPS sensor.
 
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Mine likes to buck a little bit out of first gear when I first start her up. I’ve always just assumed it’s not warmed up quite yet. Never an issue after that.
 
At what year models do catalytic converter’s come into to play-
 
AndyG said:
At what year models do catalytic converter’s come into to play-
Click to expand...
Every TJ came with factory cats (if there's any exception I'd assume it'd be export models) but a clogged cat doesn't usually show up as random bucking - it will just fall flat on its face and possibly blow out any gaskets upstream of the converter.
 
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Hey man, I had a similar issue about a year or 2 ago and had narrowed it down and decided it was the map sensor at first. After replacing it it was clear it was not the problem and -after going to a mechanic I know it was discovered it was actually a short in the wiring harness that goes to the map sensor. According to him it was a somewhat common thing because of how/where the wire is tied down. Could also be one of the things listed above but I’d check it out.
 
Axl98 said:
98 TJ with 147k miles , while accelerating it’s started bucking and jerking and hesitating.
Sounds like the fuel isn’t getting to the engine right

Could it be a clogged fuel filter ( which is inside the fuel pump)
No CEL, shifts fine (it’s a manual)
Thank you
Click to expand...
Before you buy a fuel pump, how does it run when it's cold, before it has started to warm up? If it runs ok before it warms up that problem is likely caused by a bad O2 sensor.
 
Jerry Bransford said:
Before you buy a fuel pump, how does it run when it's cold, before it has started to warm up? If it runs ok before it warms up that problem is likely caused by a bad O2 sensor.
Click to expand...
It seems to get worse after it warms up, it bucks a little at 1st gear but even when it has been running for a while and it is in 4th or 5th (If I am lucky to get to 5th lol ) it gets pretty bad at times.....
 
Axl98 said:
It seems to get worse after it warms up, it bucks a little at 1st gear but even when it has been running for a while and it is in 4th or 5th (If I am lucky to get to 5th lol ) it gets pretty bad at times.....
Click to expand...
But how is it when it's still cold? Does it drive and accelerate OK then?
 
Jerry Bransford said:
But how is it when it's still cold? Does it drive and accelerate OK then?
Click to expand...
It is very Jerky when cold, between 2nd and 3rd gear it may be a little smoother but then by 3rd/4th gear it can get very rough.... It hesitates like the fuel is not getting to the engine.... like something is stopping it.
So yes, it is bad when cold and warm but seems to be worse when warm
 
Thanks for posting all this - anxious to find out the issue- when you learn and share, we learn (then act like we know it all later)

Hope the pump gets it- Blaine’s tip on an ATV lift is good advice- very stable and controllable.
 
Axl98 said:
98 TJ with 147k miles , while accelerating it’s started bucking and jerking and hesitating.
Sounds like the fuel isn’t getting to the engine right

Could it be a clogged fuel filter ( which is inside the fuel pump)
No CEL, shifts fine (it’s a manual)
Thank you
Click to expand...
Hey I have a very similar problem right now. I made a thread about it as well but thought to search around because my thread didn't help much. Is your jeep constantly stalling as well? I've replaced the map sensor and the tps sensor. Hasn't done the trick. I'm thinking it is a short in the wiring harness but I have no experience with electrical so I'm not sure.
 
leonardo said:
Hey I have a very similar problem right now. I made a thread about it as well but thought to search around because my thread didn't help much. Is your jeep constantly stalling as well? I've replaced the map sensor and the tps sensor. Hasn't done the trick. I'm thinking it is a short in the wiring harness but I have no experience with electrical so I'm not sure.
Click to expand...
Knock on wood it never stalls
 
Ok so I thought it was fixed with replacing the coil and distributor but it’s started to do it again…. We are going to change the upstream O2 sensor, map and tps sensors and fuel pump (waiting on fuel pump as I can’t easily change it where we live cause they don’t allow it so I’m hoping it’s sensors before I have to do the pump)
Has anyone solved this issue without changing a fuel pump?

It does run a little better with a new coil and distributor but here is what it’s doing:
1st to 2nd gear a little jerk
Between 3-4th gear it will drive ok but it’s misfiring - the rpm’s will surge periodically
And it jerks a little

Any other suggestions welcome
Thank you
 

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