I have a '93 GMC with 4.3 TBI engine. It has 185K miles on it and has generally been trouble free. A few months ago ( about 5K miles ) I had some hesitation around 2000 rpm and it was down on power.
I replaced:
Plugs & Wires Cap & Rotor EGR valve O2 sensor
I did each of these one at a time and the 02 sensor seemed to make the most difference.
Anyway, the truck has been running well again, UNTIL this morning. On my way to work, I stopped at the bank ATM. It was running fine when I shut it off, but when I started it back up it had a terribly rough idle. It shudders terribly, and is very under powered under accelleration until I hit about 2500 rpm, then it seems to smooth out and run fine.
Any ideas what may have happened?
Michael