missfire only in overdrive

has anyone had a problem with a missfire only in over drive when the revs drop to 1500-2000 rpms. above that it goes away. is it possible that one of my coils on my 3.4 is going out?

if its your coil going out you would have a real bad dead miss though out the rpm band. First I would say check your plugs and wires make sure they arn't physicaly damaged or worn out.

i just put new plugs and wires in approx 1 1/2 months ago. is it possible that the heat from the v-6 has wore them out this fast?

depending on how you roughted them its possible. The most common problem I'v seen on the 3.4 when it comes to wire roughting is keeping it away from the egr tubes. Got me once, was working in a hurry and not thinking. But also you may have gotten defective wires. Go over every square inch of each wire and see if you see any burnt spots where the spark may have jumped out of the wire though the insulation and grounding out some where.

I had the same problem with my camaro. It drove fine in all the gears except in overdrive. The engine ran rough in th 1500-2000rpm range. Pull it into drive ran smooth. I replaced to plugs, wires, egr. Problem not solved. The Problem was a bad fuel injector. Replaced it and the miss went away. You can check them, make sure there's no leaks or cracks in the injector. Hope this can help you.

how would i go about checking the injector to see if one is bad, would i have to have them sent out or is there some other way cause i'm not showing anything on my scanner when it happens.:confused:

has anyone had a problem with a missfire only in over drive when the revs drop to 1500-2000 rpms. above that it goes away. is it possible that one of my coils on my 3.4 is going out?


Is it an automatic? A lot of times when your torque converter's starting to give out it does a "misfire" condition in overdrive when the revs drop. It's not actually misfiring, but it's the torque converter slipping; feels almost like a misfire, but it's really not.

i just rebuilt the trans & installed a new torque converter.

one way you can check for a faulty injector is unplug the wires to the injector one at time, while the engine is running, listen for the one that DOES NOT cause the engine to drop. You can also use a screwdriver, by placing the tip on the side or base of the injector and listen for a tapping sound by placing you ear on the handle, if you do not hear anything the injector is not working. However the injector may not be bad, but just cloged. This is one thing that will not show up on you check engine light. The obo+ oboII system mainly deals with the emissions, like o2 sensors. Give it a try and let me know how it works out.

i listen to my injectors, i hear all of them clicking like they r working they all sound the same, i ohm'd out all my power packs they are all within spec. i checked all the wires and they r good and not arcing anywhere that i can see. i disassemble my egr valve and cleaned it, put it back on . i am going out tonight so i will let ya'll know if that fixed it.