High Idle


New Member
First teggy and my first forum post! Please help I have a 93 gsl sedan b18a1. I had a low surging idle prob so I replaced my IAC. Now my idle after warm up sits right at 1200 (beautiful idle no missfire or surgeing) i have adjusted timing down and idle screw new TPS as well calibrated perfectly to .5 at close. My question is, is this idle to high and if so what else can I do to lower idle?


New Member
I can’t find the post I used to originally set mine but I should be able to walk you in the right direction from memory.

First off, the IACV (behind intake) is a variable valve that uses voltage to open and close. It is tied into the FITV (under throttle body). The FITV has a wax pill in it that sets plunger depth depending on temperature. Second, both should be able to be taken off and ports cleaned and lubricated just not with WD40, I use aerokroil (FITV can be readjusted if you can find the right information and may be needed).

If you have adjusted the throttle cable you may have to start by readjusting that first, there should be a small amount of slack that allows the butterfly in the throttle body to close fully. Make sure anything that draws a load is turned off such as AC, defrost, radio etc. Make sure coolant lines are purged of all air.
To adjust IACV bring the car up to normal operating temperature and pull wiring harness off IACV, at this point the RPMs should drop. Set to approximately 500-600 RPMs through idle air set screw then turn off car. In the under hood fuse box pull 10A ECU fuse and 7.5A back up fuse for about 15 min (top left and bottom left fuses), this should reset your computer. Replug IACV and let motor cool. After cooling start and let idle bringing it up to temp then take for a test run under normal driving conditions, this should allow the ECU to adjust normally. The process may have to be repeated to fine tune but your idle after warmed up should be roughly 800 RPMs.

Hopefully I’ve been descriptive enough and accurate and this solves your issue.