I have a 1992 pickup with the 22R with EFI and when motor is warm and you are just sitting there with foot on brake at a stop light the idle drops for 1000 to 500 and then back up to 1000 for couple seconds then drops and comes right back up again until you take your foot off brake and with foot off brake it idles fine whats up please help!

 

Brake booster works off of engine vaccum, I would guess you have a vaccum leak. Check the rubber hose running to the brake booster.

 

Try turning down the idle to spec......about 750. If the Idle is to high, the ECU will try and cut it down when the foot is on the brake. This used to happen to my truck when the idle up came on for the a/c. as soon as i adjusted the idle speed for the compressor to kick on to, it was fixed.

 

This has been covered hundreds of times. It is not the brake booster.

The idle speed is set too high. Set it for UNDER 1000RPM! 750-800 is best. I like mine at 900 though.

 

Man do I hate it when I am wrong

 

This has been covered alot. I know i even have a thread about it. Turn your idle down, problem will be solved.

 

Idle speed at 1000..... when the brake is pressed the ECU reads that as a stop situation (and it is) so it cuts the idle..... the rig idles back up to 1000..... the ECU says "no" and cuts the idle...... up and down and up and down....


Set the idle to about 800 and you will eliminate this issue.