BIZARRE end to the hunting/stumbling idle issue on my ‘95.

any4xx said:

Just to refresh: I rescued the son-in-law’s ‘95 Sierra K1500 in February after it had sat dead for 12 years. I got it running quite well, but there was a hunting idle accompanied by a slight off-idle stumble issue that I just couldn’t get rid of. I tested individual parts, rebuilt the throttle body with new injectors, and eventually replaced every single component on top of the engine. I used AC Delco parts with only a couple of exceptions. In the end I was convinced that my problem was with the EGR valve. I tried TWO AC Delco EGR valves on it and neither cured the issue. I also bench-tested both of those valves and both were working properly. Sealing well when closed and holding diaphragm vacuum without any leakage.

I was on the list here waiting for the OBD-1 scanner so that I could dig more deeply into it.

I finally sold the truck to my buddy who had full knowledge of the issue but wanted it anyway.

Yesterday he took the truck to an older mechanic who says he worked at a GM dealership in the 90’s and was sure he could fix it. And he did. By replacing the EGR valve! The mechanic told my buddy that AC Delco was NOT the OEM supplier of those EGR valves and he replaced it with the OEM valve, adding that the AC Delco valves are cheap and never work right. Huh???

So the truck is fixed and runs great with whatever top-secret brand of EGR valve he put on there because the two “cheap” AC Delco ones I tried were junk. Oh, and he wouldn’t say just what brand is on there now or why this magic EGR valve cost $260.99.

I post this mostly because during my quest to fix this issue I saw so many of you fighting the exact same issue. Hopefully this will help someone else.

Thoughts please?

Click to expand...

Hpilot said:

Did you happen to check out the linkage? On my 95 c1500 I noticed a bit of lag between pressing the pedal down and the carb opening up. This can give a bit of a surge when trying accelerate. Our old feet aren’t as responsive as they should be. Good luck.

Click to expand...

L31MaxExpress said:

You must be registered for see images attach

Click to expand...

1madmouse said:

Most parts distributors have dark mode that is why We have to be educated or experienced enough to know what's up. It's a jungle out there

Click to expand...

Schurkey said:

Is "Dark Mode" something other than the background color?

Click to expand...

Caman96 said:

Exactly, not like RockAuto has Dark Web site selling stolen or fake auto parts. Other than Acdelco

Click to expand...