I got a ported BR TB installed back in May. Afterwords I'd sometimes get a CEL for irregular high idle or something to that effect. After a few months of hearing my loud exhaust at stop signs and red lights I bought and installed a new IAC last Friday. On the first test drive the Idle was at about 950-1050 consistently when I would come to a stop. That was great! Previously around 1300 or so. Now when sitting in traffic the car can go anywhere from 1500-1800. It's like my problem has gotten worse now. Can I manually adjust the idle screw or is a retune required? Thanks for any info or opinions.

 

Very surprised there are no replies to this. I thought this would be a easy question. I'm going to disconnect the battery for a little and see if I have any luck.

 

Retune not required, but an idle learn probably wouldn't hurt.

Disconnect battery for 5 minutes. Reconnect and start car up, idle for 10.

But my other question is this, Did you set your throttle position sensor back to the correct position. You could possibly see what parameters it is reading with a scanner.

 

I adjusted nothing. I did do the relearn before noticing your reply just now. It brought the RPM's down considerably, but they still hop up around 1300. I'm going to have a tuner take a look. Thanks.

-Brian

 

I had the exact same problem. I changed the IAC and o ring which fixed the problem. I had the exact same symptoms as you. It would be fine when the car started but after driving around the block the RPMs would shoot up to 1500-2000 RPM. Since you just changed the IAC, double check the oring is installed and seated correctly.

 

you will have to park the stepper with Evoscan and the adjust the BISS valve, then reset the battery, that should solve your problems

 

I would do all this.

But first, I would reset the battery to erase all the "learned" ISCV stuff. Then install the new IACand use EvoScan to set to 850 -/+ 50, as stated by the FSM.