i swapd my 94 civic d15b7 for a 96 d16y7 now the check engine light is on n when i start it cold the idle revz btween 1500 n 2000, bout 10 minutes later or wen it warms up enough it stops reving n runs jus fine....does anybody kno what the problem could be? i really appreciate the help.

 

so, you got the same ecu?
and if so, then it is odb I.
taking a reading of the led's and post the results.

 

Dude, just pull the code from the ECU. You're getting a CEL. It's dying to tell you what's wrong.

 

ok i did the CEL test a piece of wire n the light flashed 1 long n 4 short flashes so im guessing its 14...i check the code list n it says its the IAC valve is correct, if so is it hard(d.i.y) or xpensive(shop) to fix? oh n also the SRS light was flashing continuously the whole time i was doin the test does that mean anything?

 

don't know srs
your symptoms seems to be the iacv.
i would do more checking before i would replace it - considering that is cost about a couple of hundred (at least for the 88).
and your problem could be the ecu.
when it is idling and you turn the ac on, what happens to the idle speed.

haynes has procedures for checking the iacv - i would check that or chilton's.