Hi

Re 98 Camaro Z28, A4

Makes a loud popping sound from the exhaust only under WOT. Engine runs rough when it happes. Under partial throttle it is ok. Thought at first it was a misfire, but the scan was negative. I checked the exhaust and it is tight. I cannot find any leaks at the manifolds, cats or Y pipe. Also, no physical contact.

Should I be looking at AIR or EGR gaskets. Any help is appreciated.

Thanks JA

 

have you done any recent mods?

 

Hi

Yes, I just swapped the headers out for the stock exhaust. All gaskets are new and everything is tight. Thinking I screwed up somewhere.

JA

 

Did you put the exhaust in with the spark plugs still screwed into the heads? You may have cracked a plug, even though you don't find any missfire from scanning.

 

you may also have a bad plug wire. it will not arc out, it will fail under heavy load though. pull the wires and do a resistance check. the readings should all be very close to each other (ohms)

 

Hi

Did a little more investigation, it is not a leak but definately a misfire at WOT. No exhaust leaks.

Plugs were out when the swap was done. They were inspected and in good shape. The shop told me they were carefull with them.

I think I will take it back to the shop and ask them to swap out the MSD wires for the old GM ones. If that does not fix it, I assume I am screwed. Without it showing up on a scan it will be hard to fix.

Thanks JA