[scottfab]

You might want to clean out the drain hole while you're in there.
Put a long wire down the hole with a small piece of rag tied to the end.
Then get under and pull it through. Depending oh how much crap comes
out you may want to do it again.

Another thing to consider when you've got the plenum off is to either loosen
and retighten the two grounding lugs on the top of the bell housing or take the bolts out, clean the grounding surface and lugs and apply dielectric grease. These surfaces oxidize over time and cause bizarre and random electrical issues. To do the later you have to be good at doing things by feel since vision it tough in those tight quarters.