i have a 98 civic dx, i put a 99-00 sohc dx swap into it, i switched the engine harness to a 96-98 lx harness and the car idles weird at 1500 and also has a high idle...does anyone know if the 96-98 dx motor and wiring for the iac is different from the 99-00? and if so how do i fix? thanks!

 

i dont think there is a difference from the 96-98 and the 99-00. there could be many things causing your car to idle high. check the following:

vacuum leak
IACV
FITV
spark plug wires
spark plugs, check gap
bubbles in coolant
timing(adjust if needed, if timing is on marked but idle still high, check for skipped tooth on cam gear)

quick question, what you mean you switch engine harness. did you mean the electrical harness or the motor mounts. if electrical harness this could be your problem.(but wouldn't hurt to check the others)

 

i switched the complete wiring harness on the motor to a 96-98 lx civic harness...i also have a CEL on also and @ 1500rpm's the idle sits there and goes up and down like its stuck

 

what CEL is it reading? and from my knowledge that harness should be fine unless its not OEM. aftermarket harness on hondas are known to have cause problem and this could be your idle problem.

 

no it's a stock harness...i just cant figure why it's being weird the motor ran fine in the 00' civic

 

up anyone?