1994 GMC Vandura 3500 Q&A

1994 GMC Vandura 3500 Question: wha is the timing?

when i goin the the hiway and is an slope , the speed go down drasticly from 65 to 35 mph., lus power.. -
Answer 1
sounds like a clogged cat converter. take it to a shop for a check to verify and a bid for repair. Roy -