It starts to chugg or skip when driving at a consistant speed..

No lights on

Scanner will show the problem, even without light on. A scanner, not a parts store code reader!

Could it be the coils??

could be any part of the ignition system

No luck with the buick dealer!? Jus t $$ it seems to only do it in top gear at 35 or 70 time to give up on this one?