i have a 1985 chevy c10 5.0L its a fixer upper. was running really good now idles rough when it does idle but most of the time it dies, it will stay running as long as i give it gas, any suggestions


Asked by May 28, 2014 at 09:03 PM about the 1985 Chevrolet C10 Base

Question type: Maintenance & Repair

idles rough, but mostly dies at stop lights or anytime idling, while run as long as i give it gas. i bought the truck as a fixer upper had been sitting for a couple of years, change plugs and started right up when i bought it. checked plugs again last night a little wear not bad cleaned them up with sand paper and reinstalled , mad no difference.

3 Answers

Andrew Mauch

Sounds like a vacuum leak. Check all the little rubber hoses for any splits or cracking.

Dan Araujo

I agree with Andrew.


Things that can make this 305 idle rough:1. Carburetor low idle set too rich or too lean. Don't adjust this "willy-nilly" Read a mechanic's manual on the procedure and follow it as closely as your carburetor will allow. There are a couple of good YouTube videos on how to do this, too. Take a moment to watch them. 2. As others have answered, vacuum leaks cause a lean condition. Make sure all vacuum lins are connected or plugged befor adjusting the carburetor. 3. Check to make sure the vacuum hose from the PCV valve to the Fuel Evaporator Canister is hooked up and in tact. This will raise your idle by 100 to 150 RPMs. (Replace or at least clean the PCV valve while you are at it) 3. A stuck EGR valve. Disconnect and plug the vacuum hose to the EGR. If your idle RPM increases and smooths out, replace the EGR valve. 4. A bad or failing HEI module (inside the distributor) nothing to fix here but replace the module. 5. A bad or failing ESC module (Electronic Spark Control (current name; was called Electronic Control Module or ECM - some call this a Computer Control Module or CCM - it's all the same thing) located under the dash below the heater vent. This controls the timing advance based on detected vibration of the engine, and if going bad can cause your low idle to be inconsistent and unpredictable and causes poor or choking acceleration. I recommend you replace this with a traditional HEI, vacuum and mechanical advance distributor - not difficult to do and cost less than $200. Do not follow bad advice and jumper the green and black wires at the connector to the ESC . This eliminates all advance control entirely and greatly decreases gas mileage. It will get you back to the garage but it is NOT a fix. 6. A clogged fuel filter (as mentioned by others). 7. A gummed up carburetor. 8. A bad or marginal fuel pump or clogged fuel lines back to the tank. Some C10s came with a dual tank system and the solenoid switched valve that controls which tank is supplying fuel can go bad or leak. This causes your fuel pump to lose it's prime by sucking air through the valve housing. 9.Gremlins

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