You are not going to beable to bully the dealer into replacing the intake, just because a few people had issues. he will say "Move along, the next fish is coming". A 46,000
LeSabre shouldn't be that hard to move. The 3.8 is a BULLET of a motor, and they pretty much last forever. I know the 3.1 had intake gasket issues, and then it would leak coolant.