Changed plugs and now misfiring

**dieselden** · 04-15-2011

I just changed the plugs on the wifes 06 with 3.8 supercharger.
First I put in a set of plugs called E3's. The car was misfiring and backfiring. I checked all the plug wires and looked for any lines I may have knocked off, and still nothing. So I talked to a GM tech and they said the 3 pt spark plug is not good on a supercharged motor so I put the factory plugs back in. Took it out for a test drive and everything seemed to work great. The wife took the car out to a town about 100 miles away. She said it almost never made it there because it was backfiring so much and engine light came on and was flashing.

I know there is probable threads on this, but I have to leave on monday for work and going to be gone for a month. If I could get any ideas I would apreciate it.

**Fivefingerdeathpunch** · 04-15-2011

Are there any codes that can be pulled to see exactly what pulg is misfiring?

If you gunna be getting new plugs go with either the new originals or a the autolite 606's.

**dieselden** · 04-15-2011

I don't know if it's throwing a code or not, but I bought the factory ones and put them in(that was 4 days ago) and it seemed to work good till tonight.

**Scottydoggs** · 04-15-2011

have you changed the plug wires yet? or checked to see if one or more are laying on the exhaust manifolds? and make sure the wires are on the plugs all the way? and you don't want the plug wires touching the 02 sensor wires from what I've read here.

did you pull the motor forward when you did the plugs? so you could see back there better and get your hands in there better.

sometimes when we pull the old wires off they break too, you could have pulled one or more apart. the wires usually get really tight on the plugs and you need to really do the hard twist and pull on them.

**dieselden** · 04-15-2011

I didn't have to tilt the motor. I don't think I had any wires touching the exhaust, but I did have a hard time getting 2 wires off on the back side. So maybe I'll try test the plug wires on the car to see if any are broke. I can't do that till sunday night.

**Scottydoggs** · 04-15-2011

its just hard to really see back there if you don't pull the motor forward you just need to pull the dog bones, the 2 metal brackets the attach to the rat support and the front/ side of the engine, i wear 3x gloves so i got me some huge ass hands, i couldn't get my hands back there if i tried....but you can see a whole lot better if you do move it, it moves real easy too, not like you need to pry it or anything. and not to mention get a socket, 3 inch extension, and a ratchet in there. makes life much easier.

plug wire sets are like 30 bucks, its worth doing.

**KeithGTP03** · 04-15-2011

I didnt see anywhere that you changed the wires. Id just get a new set of plug wires to eliminate them all together. Its cheap and if thats not the cause, it isnt a waste because you'd need them eventually.