89 Chevy C1500 rough idle when in reverse and stalls when headlights are on

May 15, 2006 5 Replies

I am having stressfull time with my chevy truck. When start the truck it will idle fine in park but when I put it in reverse it idles extremly rough and almost stalls. When I put it in drive it runs rough when I put the brake on. Also when the truck is in park I can put the lights on with no problem, but when the truck is in drive or reverse and I put the lights on it stalls. I have replaced the air filter and the PVC valve ( the PVC did need replacing bad, but didn't solve the problem). Any help or suggestions would be greatly appriciated as I don't have any money to bring it to a mechanic.



I know you probibly already thought of this but I would be looking for a vacume leak somewhere .

Hello, Thanks for the suggestion. I changed the vaccum hoses and it didn't seen to solve the problem, any other suggestions?

I had a similar problem with the power brake vacumn booster leaking....when idling in park, press the brake pedal....try it with the windows up, then down...notice if there is a change in rpm....the diaphram is leaking and is sucking in air from the cab thru the firewall opening.....

You can miss one real easy check your vaccum with a guage and compare it to specs.

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