> wrote:
>1993 Grand Am 3.3L V6 (6-204) - Solved intermittent "Code 42 - electronic =
>spark timing" issue by replacing Mass Air Flow sensor, after checking all w=
>ires in harness (and replacing some) between the ECM and ICM, checking all =
>connections, and replacing all the other sensors. All work prior to replac=
>ing MAF improved performance but did NOT solve intermittent Code 42 problem=
>. Never got a "MAF sensor" Code 34.

So, what did the sensor strip charts say? Was the MAF sensor tracking with
throttle and were there any dropouts?

Does the MAF sensor by any chance share a reference ground in a cable with
something else? If something bad in the MAF sensor electronics was polluting
the ground, you could have seen spreading problems like that.

I have to say that's a hell of a weird one. I'm very curious what the
failure mechanism was.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."