Repair guides and support for C/K pickup trucks sold by General Motors under the GMC brand, including the GMC Sierra.

24 Questions View all

started running poorly a few days ago

My 89 GMC sierra does not have a vacuum modulator valve,it started running like crap a few days ago and shifting from first to second,it slams,shifts hard going into second. Why?

Answered! View the answer I have this problem too

Is this a good question?

Score 0
Add a comment
Black Friday
Broken doesn't stand a chance.

1 Answer

Chosen Solution

I would take it to an AutoZone and get a free computer read out so you have even an idea of where to start looking.

Was this answer helpful?

Score 1
Add a comment

Add your answer

Gary Seely will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 0

Past 30 Days: 12

All Time: 22