95 Z28 Conv M6
Ran rich but smooth. Failed emissions.
Plugs had 160,000 (I was dreading the task).
Air Filter bad - See no light...

Replaced Plugs - Bosch Plats
(About 4 hours; Superman technique from top; removed Alt to get to #2 and worked #8 from bottom. Used Spark Plug socket with 3/4 socket over it.)
Replaced A/F - K&N
Wires on tight.
Opti about 60K. (Remember ran fine before)

Now it stumbles when accelerating.
Should I be looking at the MAF?
Can it be cleaned and how?

It's great to be back here!!!

 

What is the thing before the throttle body? MAF or MAP?

 

It is your Bosch platinum plugs causing the problem. I know you don't want to change them out again, but put in the stock AC Delco's or NGK TR-55 non platinum plug. Your problem will be gone after that. Same thing happened to a buddy of mine who installed the Bosch platinum plugs on his firehawk.

Jeff

 

If the MAF Cleanoing doesn't work, looks like plugs again.

Lesson Learned. New type Air Filter (K&N) brings additional variable into the mix.

 

UPDATE:
Cleaned MAF, same symptom (ran better, no more popping).
Disconnected MAF same symptom.
Replaced Bosch with AC/Delco. PTL - Symptom Gone!!!
Sure enough a couple of Bosch Plugs had loose tips....

 

I have bosch plat's on my car now and it runs fine. Ill be switching thoes out next time i take a trip to summit. Thanks for the heads up.