Idle issue
 

Ok, so i have a 93 FD, Auto trans with a power fc. And when its just idling, the car will sometimes go idle from 900 to 100rpms and and then jump back to 900 then drop to 100 and it'll keep doing the same thing over and over again. Sometimes it'll go up to 1100 rpms. I noticed that when it fluctuates like this, if i turn on the air to full blast the idle will stabilize to about 900rpm, or if i push the A/C bottom on the car will idle steadily even though the A/C has been removed. But now if it fluctuates like it does, and the air is on full blast or the A/C light is on, it still wont idle steady, dropping from 900 to 100 and going back up, etc, etc.

how do i fix this?

Hi! check for your tps ajustement! Do you learn the idle to your pfc? If not, do it! :)

Eric

Simple--search!! Kidding.

You may want to check your ground connections for corrosion. It is not uncommon for poor grounding to cause these kinds of fluctuations. The three main ground points that get ignored are at the firewall passenger side, lower driver-side of the engine block, and driver's side fender below the fuse block. Also check the battery terminals for corrosion as well. Simply said, sounds like an electrical issue to me.