Brownie289

1992 G30, high idle, replaced the idle control valve, was running better.
Now when I drop into gear it stalls, like it’s getting no gas.
Then hard to restart.

New throttle body time?

Thanks!

Triaged

I'm guessing 5.7l?

You can make your own cable for the scan tool... I might have thrown out the one I made way back when.

https://charm.li/Chevy%20Truck/1992/.../Idle%20Speed/

Triaged

WinALDL - 160 baud ALDL reader

Brownie289

Tried a code reader says no issues
Yes it’s a 5.7.

Triaged

You aren't looking for a code. You need a scan tool that can look at the IAC count. There are lots of options for OBD2 but with pre-OBD2 ALDL you're looking at either expensive or DIY. I provided the DIY cheap version. Just need a serial to USB cable, the program, and a DIY cable made from some parts from "radio shack". Good luck finding a local electronics store.

Brownie289

Yes thank you I used a scan tool. Count was 1 - 2. Meaning ok.

I did disconnect the battery after too, supposed to clear the ECM.?

Brownie289

The only thing I have done to it was change the idle control valve…

Triaged

1-2 is too low isn't it? Charm says 5-30. Do you have a vacuum leak? Bad PCC?

Brownie289

I haven’t really focused on a vacuum leak, just because this came on suddenly after I changed the idle control valve, actually it ran better after I changed the valve, took it for a ride performed well. A few days later this problem developed.

The book that came with the reader said a flash of 1 then 2 meant no issues.

mountainmanjoe

Code 12 indicates the computer's self-diagnostic system is functioning properly.

It does not indicate "no issues", since you will still see code 12 along with other trouble codes.