CEL and monitors problem - Need some advice please!

[911monty]

Originally Posted by impboy

I'll try to be brief...


I think I may need new spark plugs, maybe new coils, or maybe new O2 sensors. It’s been awhile since any of those have been replaced. BTW, the car has 135,000 miles on it.

Any advice and direction would be very much appreciated!

Service interval is 60k for spark plugs on 01. If you don't know when they were changed this would be the first thing I'd do.

The OBDII has a two trip detection logic. Meaning a code is stored as pending on first trip then sets the MIL on the second trip. Probably why the readiness monitors status changed but the codes popped 2nd trip after clearing.

PS About those plugs, make sure the engine is stone cold before attempting to remove, AND if they have been in for an excessive amount of time they could have carbon buildup. If they don't unscrew easily then loosen and tighten alternately to try to minimize thread damage in the aluminum heads, don't just unscrew with a bigger wrench.