I'm still trying to run down my "fails to idle" at operating temperature problem. As a reminder, this problem developed after the TB unit gasket was changed. Your suggestion to adjust the set screw on the TB sounds like the solution, but I can't seem to locate it. Again, this K5 is 1987, 350 with manual trans. DO all TB have the adjusting screw your speaking about? I've tested the O2 sensor, IAC valve, MAP sensor, TPS, and replaced some vacumn lines just to make me feel good! I thought because the stall occurs primarily when I'm stopped and my foot on the brake, I would find a vac leak. Tested every vac line/connection I could find by spraying brake cleaner and hoping I would detect a leak. Vac gauge shows 19 psi at idle and 21-23 psi above idle. No codes in the computer memory. I did the jumper wire thing with key on (only code 12) and while running. While running, even at operating temperature the truck runs in OPEN loop (2 1/2 flashes/second). At what point (if ever) does it run in CLOSED loop? As you can tell, I'm a slave to the last article I read!! Speaking of reading, my Haynes manual is disappointing. Tried to find a Helm's manual at their web site and doesn't appear available for 1987. I'll do a fuel pressure check next weekend. I still need HELP.