Spark Plugs Firing
 

88 S4 N/A... I'm tracking down a loss of power and just noticed that my bottom two plugs have a light black coating (looks normal) while the top two are much cleaner. I am also have some slight backfiring but not major. Idea's?

P.S. I did replace the plugs with the proper NGK plug and this did not improve the situation.

Thread moved to 2nd Generation Specific, does not belong in Build Threads

It sounds like your Trailing plugs aren't firing. This doesn't sound like a dead trailing coil, as your tachometer would be dead too. Try checking the plug wires against the FSM's specs?

Slight backfiring?

just double check that you put the trailing plug wires on the correct plug.
Not having the trailing wires correct will tend to make the engine run "funky" and yes,backfiring will happen!