93 ecu on a 90 swap. Options

[lagos]

I installed a 93 mr2 ecu in my 90 3sgte. I repined the harness plugs to work with the new ecu. The car drives perfectly but wont idle correctly. It will sit at 650 rpm and want to stall out. Then after a few min of driving it will bump itself up to 950rpm for the rest of the drive. If I put the car in diagnostic mode, it will stall right out.

I was thinking maybe it has something to do with the IAC valve, but wannabe confirmed they should be the same. I know 93s have a slightly different throttle body, so maybe that has something to do with it.

Anyone here use a 93 ecu on their 90-92 motor?

[lagos]

I unplugged the IAC valve. Car idle went up. Plugged it back in, idle went down. So the IAC should be working fine.. heh.
I ended up adjusting the flat head idle screw on the throttle body to bump the idle up from 650 to 800. At least it doesn't idle to the point of almost stalling out now, but after a few min of driving it still settles on 950, and doesn't like to idle correctly when in diagnostic mode.

There must be something different about the 93 throttle body.... or maybe some other issue going on.
Besides that the car drives smoother and better then its ever been on the new 93 ecu (sard rom tune! ).