Pontiac Motor Locked up
 

I have a '99 Pontiac Grand Prix. I think the upper intake manifold plenum is bad and has fouled out my sparkplugs. But, I was told this could also lock the engine up. What is the best way to go about this problem?

Jeff

RE: Pontiac Motor Locked up
 

Apparently early 3800 series II motors like the 1999 had plastic intake manifolds that were prone to problems much like the ones you've experienced. I bought my 1999 in 2002 as a lease return and it has the aluminum manifold. My guess is GM may have replaced either as a recall or to cover their ass on the lease vehicles.