98 ram backfiring

[thunder14]

I have a 5.2 and have brought in to two seperate places and they can,t figure out whats wrong. What it does is you start to drive off and when you accellerate slowly its like the gas does not want to go through and then it backfires.Sometimes the rpm start to jump when its about to shift but it always backfires. Trouble is it does not do it all the time but usally when I start it if it idles rough it usually will do it.Other times it runs great then i will turn it off for 10 minutes and then it does it. They have done computer scans on it but everything comes up ok but they know something is wrong. The question is what? Also no check engine light has come on.

[BleedDodge]

On my truck we couldn't figure it out for the longest time, but it was the 2-wire harness that goes to the positive side of the coil. It would stall and backfire and run only when it seemed to feel like it. That wire had to be in just the right position or else nothing would happen.

It's so stupid because the wire makes such a wicked angle from where it comes from to where it enters into the coil. Right beside the exhaust manifold too, no wonder it went bad. We thought it could be everything from plugged injectors to bad fuel to no fuel, we were so stumped. All it was was that stupid wire harness. It could be anything on your truck though, but make sure to check that piece out.

[thunder14]

I had that problem before and it was the wire from my car starter. Thing is this time the truck does not stall but I will check that just in case.

[89ltd]

backfiring is a classic symptom of a bad egr valve, but I'm not even sure if there is one on yours.

[thunder14]

I tried reving the engine up when it was cold while sitting in park and I could not get to rev up to 2500 rpm and maintain it there. Once it warmed up a little then I could do it.The truck does have an egr valve. Would that be a sympton of a faulty egr valve or is it something else?

[89ltd]

I would try disconnecting and then plugging the egr vacum line and see if it helps. If the valve is opening to soon, it will idle crappy and stumble when your taking off, also may backfire.When you try to rev the engine to 2500, does it run good, but won't go up to 2500 or running rough??? Could be throttle position sensor as well.

[thunder14]

Its like gas is not going through and once I get it to there the rpm want to drop off so I have to step on it more. Then all of a sudden it smooths out and runs great.

[thunder14]

After many months I brought in to another shop and he figured it out. It was the upstream 02 sensor.