i just recently turboed my 1.8 and with the iac disconnected from the pipe that comes out from the intercooler it idles fine for a second then it will drop down to under 10:1 my aem wb doesnt go that low. then when i hooked up my hose going from my iac valve the the pipe coming out from the intercooler it doesnt idle for **** and its only pulling like 10hz in vacuum when it should be pulling like 20. i have a begi rrfpr and 440cc rx7 injectors. i am stumped and dont know why its idling like this. i am also running the stock ecu.

 

you might want to consider getting a piggyback ECU, or even a standalone, althougt you may not need a standalone... but you can tune the fuel tables, and make it idle much better.

then again... may be something mechanical... if your still using your MAF, then disconnecting the IAC can create an irregular AFR, as for when it is connected... the fpr may not be working?

.. i tried.

 

Your injectors are too big for the stock ECM .......

 

this.