Misses and backfires when road is bumpy

[Skulljeep683]

I have it narrowed down to when im driving while in gear and i shift hard or when i drive down bumpy terrain, it misses and backfires and occasionally dies upon stopping, also it will have a really high idle after the backfire or miss, at which point it returns to normal upon a complete stop. otherwise at idle, or at a stand still it runs fine.

 

[desertrunner]

Is it carburated or injected?

 

[Bounty__Hunter]

He lists a TJ in his profile, they're all fuel injected. Sounds like a short in the wiring to the crank position sensor, some even have a bad connector.

 

[RudeDog]

Yeah, I'd 2nd an electrical short. Check all wire connectors, connections, wires routed thru firewall. Do as many as you can safely with it running: Check-flex-wiggle-tap everything you can to see if you can get it to act up.

 

[Skulljeep683]

Yes it is injected andi did the wiggle test and nothing happened kept running fine... i also just replaced that senseor 3 days ago and it got better for the one day, and then it started up again...

 

[Bounty__Hunter]

Yes it is injected andi did the wiggle test and nothing happened kept running fine... i also just replaced that senseor 3 days ago and it got better for the one day, and then it started up again...

Where did you get the replacement sensor?

 

[Skulljeep683]

5 days ago

 

[Bounty__Hunter]

Where?

 

[JPNinPA]

Check the intake and the for leaks. Also check the TPS ace IAC connectors. If it backfired through the intake you may want to clean the TB and IAC.

 

[Skulljeep683]

Where?

in my driveway??? unless you mean where it back fires then in the city streets and worse over train crossings??

 

[Skulljeep683]

Check the intake and the for leaks. Also check the TPS ace IAC connectors. If it backfired through the intake you may want to clean the TB and IAC.

it'll back fire through the intake and also through the exhaust, its violent and rapid too, dropping in 1000 to 2000 rpm intervals and launching back up to where i was running the motor.

 

[desertrunner]

It sounds like the timing goes screwy.. ignighting way early or late... Maybe both? IDE double check ur crank sensor..

 

[desertrunner]

Also, check all ignition stuff like the distributor cap plug wires coil...

 

[Bounty__Hunter]

Where did you get the replacement sensor?

Where as in where did you purchase the sensor? It has a lot to do with the quality of the part, especially important when it comes to sensors.

 

[Vanover]

Could it be a bad body ground?

 

[Skulljeep683]

Where as in where did you purchase the sensor? It has a lot to do with the quality of the part, especially important when it comes to sensors.

I got it from Orieleys auto parts, i paid 90 for the high end lifetime sensor.

 

[Skulljeep683]

Also, check all ignition stuff like the distributor cap plug wires coil...

that was all replaced some 10,000 miles ago, i will check, but its all new.

 

[Skulljeep683]

im a bit mad at the jeep and ive renamed it Murphys Law since i cannot seem to find this problem, ive burned up my new tire fund just trying to get it driveable. hopefully i with any luck i can find the problem and im open to more suggestions guys. thanks for the input.

 

[JPNinPA]

What brand CPs? If you have a distributor check it is not loose.

 

[desertrunner]

I've seen a lot of people have problems with recently replaced just because one nut or screw was forwgotten somewhere.... My sister actually had her oil plug bolt come out on the freeway..