1979 Chevy Truck engine won't idle

VIRISH

MEMBER
1979 CHEVROLET TRUCK
6 CYL
2WD
AUTOMATIC
280,000 MILES

I have a 250 6 cylinder that won't idle properly it idles high then low then high for about 3 or 4 min then stalls I've tried adjusting carb with little to no results it just won't idle smoothly and stay running.

Saturday, December 20th, 2008 AT 6:23 PM

3 Replies

BUDDYCRAIGG

MECHANIC
2,262 POSTS

Will it run after it's warmed up.
Maybe you just need to rebuild the carb.

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Sunday, December 21st, 2008 AT 2:32 AM

VIRISH

MEMBER
1 POST

Its getting better since I sprayed carb cleaner and fixed a few vaccum lines that were bad but it still wont idle smoothly then I ran out of gas in the truck and will try some more when I get more gas in truck when it idles it revs up the down for maybe 5 min then stalls can you give me an idea why it revs up and down what I should adjust or fix or replace if need be? And on the rare moment that I have been able to put it in gear and keep it running it wants to run away I have to really apply heavy braking to keep it from moving any suggestions there as well? And thanks for getting back to me on this I really appreciate it
vern

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Sunday, December 21st, 2008 AT 11:03 PM

BUDDYCRAIGG

MECHANIC
2,262 POSTS

About the reving up and down.
Could be fuel pressure.
Carb needs rebuilt.
Choke adjusted.
Combination of accelerator linkage and motor mounts.
Vacuum leak.

The truck wants to go when you put it in gear because the idle is too high, anything above about 1000rpm will try to push you into the street, even if you have your foot on the brake pedal.

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Sunday, December 21st, 2008 AT 11:20 PM