The tranny is not slipping if you speed up it goes away??
It starts to chugg or skip when driving at a consistant speed.. on 1999 Buick Riviera
Have it scanned, sounds like misfire! Light on?
No lights on
Scanner will show the problem, even without light on. A scanner, not a parts store code reader!
1 more answer , 3 more comments
agree with pushrod or lock up solenoid malfunction
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?