I am having an issue with my 1998 GMC k1500, if I don't drive it for a day or longer I have to pump the gas pedal slowly to get it to start. Lately I have also noticed the engines revs up on its own. For instance at a stop light it will go to about 2000 to 2500 RPMs then back down every so often. Any ideas what this may be? Thanks.

 

vacuum leak maybe? or fuel related problems since you have to prime it in the mornin. Check out the fuel pump and fuel pressure regulator

 

Possibly your egr valve...has your truck randomly stalled at while idleing?

 

The fuel pressure pump filter and regulator are all about 3 months old. And the truck has not ever died idling. The engine is knocking and I have it set to be replaced with a crate engine this week. But if it is a censor issue will it still occur? Thanks.

 

I have noticed after a week of driving it that it sometimes smells like gas and it also reves up to 1000 rpm from 500