I am going crazy with this issue on my 1999 3.9 V6 Dakota. When I start it, cold or warm, the truck runs ok. 2 minutes into it, the truck starts misfireing and when you accelerate more, the truck pop's/backfires at the engine level (manifold) and not at the tailpipe. I have already had a fuel injector service performed, tune up(plugs/wire/cap rotor). There is NO code being read from the computer nor is the check engine light on. The really odd thing is when the misfire/hesitation begins 2 minutes into starting, if you turn off the vehicle and restart it the issue goes away.....?

Any feedback is much appreciated... Brian

 

Have your cranck sansor verify

 

How do I have the sensor verified??

 

My mechanic guy, hook up a scanner ( probabli a scope ) and the scanner detect a miss always at the same cylinder. So we change the cranksansor and the problem is fixe.

Note : If you have to replace the cranksansor, do not use a generic, install a chrysler parts ( the original one ) I tried to install a generic to save about $20 but it had the same problem. With the original one it's now perfect.

 

Mine ('97, 5.2l) did the same thing after i changed the wires. Turns out I managed to cross 2 wires (even though i did them one at a time). Did the problem start right after the tuneup?

 

Tilouis,

I replaced the cranksensor with an OEM crank sensor. The truck is still doing it. You start it, it runs for a good 2 minutes then it starts loading up and hesitating. You can resolve the issue by turning it off and restarting... I think the gasket on my exhaust manifold blew because of this hesitation. I am lost..... No codes on the computer, it already has new plug wires, went through fuel injector cleaning, replace the throttle positioning sensor.... Any ideas?

 

Have your cam sensor check.Crank and Cam work together. One tell the computer one whicn cylinder to send the voltage and the other one is when to send voltage.
Another thing you can try for about 10.00 is to seefoam it. A good way to clean any deposit around valve and throtle body.
Good luck.

P.S. by the way, i had to replace my cranksansor twice because it was not a chrysler original part. Since i installed a chrysler part, i run with a truck that look and run like new

 

I know this is an older thread but I had the same symptoms and replaced my precat sensor and all was well. Just a thought.

Later
Dan

 

I had similar it was the vacuum canister hoses had split.