CUCV Idling Rough

[jpear52]

I have a 86 Blazer that has an electric fuel pump installed. Has ran perfect for years. I took a long trip in it over the weekend with no issue. After I parked it for the day, I tried to start it. It took a while. It will not run good at all at idle or low spped. When idling the rpms go up and down to a perfect rhythm. The fuel filter was changed 3 times over the weekend. My guess is it's sucking air. If so how do I find the place that it is sucking air?

Your thoughts greatly appreciated

 

[Ken_86gt]

It could be a fuel/air leak, even if not it is always good to fix them. Do you see any signs of a fuel leak? Such as sweating?

From the TM(-34):
21. IDLES ROUGH WITHOUT ABNORMAL NOISE OR SMOKE, WILL NOT CLEAR UP
Step 1. Check fuel injector pump timing. (See paragraph 3-44)
Step 2. Test each fuel injector nozzle. (See paragraph 3-36)
Step 3. Remove governor cover. (See paragraph 3-3 Check for black particles.
If black particles are evident, replace governor weight retaining ring. (See
paragraph 3-42)
Step 4. Test fuel injector pump, (See paragraph 3-44)
Step 5. Test compression of each cylinder. (See paragraph 3-2)

22. STARTS BUT WILL NOT CONTINUE TO RUN AT IDLE
Step 1. Check fuel injector pump timing. (See paragraph 3-44)
Step 2. Have assistant start engine. Check fast idle solenoid to see if solenoid holds fuel
injector pump lever in fast idle position.
If fast idle solenoid does not operate properly, perform Electrical
Troubleshooting malfunction #7.
Step 3. Test each fuel injector nozzle. (See paragraph 3-36)
Step 4. Test fuel injector pump, (See paragraph 3-44)
Step 5. Test compression of each cylinder. (See paragraph 3-2)