guys, thanks for all your suggestions...the car goes in the shop in the morning...

I am looking up the repair from 2002 and if the lower gaskets were not done I will do them now too....also, I picked up the Dorman part since its only around $90 more than the dealer gasket kit for the upper, so it seemed a no-brainer. You know it would be nice to know your engine is not going to self-destruct after in 2-3 yrs! I may have the dealer put in a 180 tstat too. I will keep my fingers crossed that all goes well and I will keep you guys posted tomorrow night when I pick her up!

The GM Dealer WILL NOT INSTALL a 180 T-Stat BTW! Just thought I would warn you first & save you the embaracement from asking them too.

If in doubt on the 99, read the casting date on the intake, and compare it to the improved intake manufacture date in the sticky thread in this forum.

I searched the previous threads and didn't see anything about the "improved" date. What date did GM start using the improved upper intake? Or, where can I find that info. in the threads?

I picked bonnie up last night, total labor was $257 including oil and coolant. the dealer said it was a failure of the plenum & gasket. They installed the Dorman Kit I provided ($145), so total was around $400....this saved me a lot $$ over the oem plenum & gasket. Hopefully I wont have to do this job again! Thanks for all your suggestions!

Did you get the lower gaskets replaced or just the upper again?

Nudge, nudge?!?!

It all depended on the old stock that was available in your area. GM WILL send out ALL old stock first BEFORE the new stock. I believe it was back in 2001 though.