missfire help
Thread Starter
Staging Lane
Joined: Sep 2004
Posts: 58
Likes: 0
From: Boise
missfire help So my car is still popping through the exhaust, I've changed 6 plugs with the last two remaining being the back two on the passenger side. I know that the car is missfiring in a cylinder and I'm positive it isn't on the drivers side. It seems to be on the passenger side. I replaced plugs when I put on headers and it has been running bad ever since. So I checked everything and thought that it was narrowed down to the plugs. But I wanted to check to see which pipes are not as hot as the others, and it seems that the two front passenger header tubes do not have as high of a temperature. I checked this by dripping water out of a straw onto the tubes and seeing how quickly it evaporated. So now I don't know if it is the plugs, but one of the rear two may just have a crack. So I'm going to try to change the back two plugs, but what else could be causing this? I'm getting a tune in the mail soon, but I don't think this will fix the problem I'm having. If changing the back two plugs doesn't fix this, I need to know what to check next. Is there any way the power packs could have been put on in the wrong order? Does this matter, and is there a way to tell if they are in correctly? I really need some help guys. I'm having withdrawls from not driving my beast 
Teching In
Joined: Mar 2006
Posts: 7
Likes: 0
From: Toledo Ohio
check your power for spark on each individual coil. Are the wires good? If they do not even look very good go to some nice 8 mm or bigger. Definately replace the other 2 spark plugs, and if they are not all the same plug you are waisting your time. This will determine between ignition, fuel, or mechanical. My car was misfiring real bad because #1 intake rocker came off and was not opening the valve. Took me 2-3 hours to take both rockers off and put them back on. You can check for bad cam/ lifter by rotating the engine slowly and put a indicator on your vlave. Watch to see they are all the same. I think somewhere around .300" is the total lift, maybe more don't quote this, but check for consistency. The exhaust is probably going to be different from he intake. Inspect each valve very cautiously. Check voltage on each injector. That only half dtermines if it is bad it does not tell if they are clogged. Next I am not sure if this stays true with ls1 but with tpi you disconnect the iac and take each individual injector plug off while running. If the motor does not change sound then that injector is not hitting.
definitely change the other 2 plugs and take a good look at them to see which one it is.hopefully you just have one fouled,even though it shouldn't be.there may be a problem elsewhere to make it foul or not be firing at all like coil or injector or as mentioned a loose rocker or broke spring.
Thread Starter
Staging Lane
Joined: Sep 2004
Posts: 58
Likes: 0
From: Boise
Found the problem, the plug in the number 6 cylinder had a huge crack in it. Car runs like a beast now. Getting a tune in the mail too. And the #8 cylinder is the last one on the passenger side.
