Question about 1979 Pontiac Firebird

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Car wants to die at idle and slow rpm speeds

I have a 1979 pontiac trans am. 4 barrell carb. It was driving fine. Took it to the shop. They cleaned out the carb and put in a new EGR valve and charcoal filter. Now it runs down the road fine, but after a few hundred miles it grew less and less willing to idle steadily without dying. Even when I put it in gear, unless I give it a good amount of gas, it will die. I plugged the tube with a pencil, but it still acts the same. Is it as simple as adjusting the idle?

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  • Master
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If they used a spray to clean the carb, then all the junk that was in the carb burned off on your plugs. You probably got a lot of black smoke out of the exhaust when you first drove the car away. Check the plugs. They are most likely gummed up with the residue from the carb cleaner. Either clean the plugs or invest in a new set. This should ensure that the car fires on all 8 cylinders. Driving on the highway, you'd be less likely to notice the problem since you need less power to move through the higher gears. If this doesn't solve your problem post back and we'll diagnose it further. Best of luck!
Greg

Posted on May 23, 2009

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  • Pontiac Master
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Got a quadrajunk carb on there? If so, unscrew the needle valves in the front of the baseplate and spray carb cleaner into the ports. Put them back in and turn out about two turns each. adjust back and forth to get the highest vacuum reading, then use a tach to get the best steady idle.Do this with the advance disconnected and plugged, adjust final idle speed with linkage adjustment.

Posted on May 23, 2009

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