my check engine light came on and i checked it at an auto parts store and it said that it had an idle system malfunction. how can i fix that without spending 300 bucks on a new unit?

 

Spend 2% of that on a can of carb cleaner and start spraying around the vacuum lines, intake manifold, fuel injectors, etc. and see if you can find a place that makes the car idle funnier, or nearly stall. Likely a vacuum leak.
You could also clean your idle air control valve if it turns out that is the culprit.

 

There is more than one IACV code for OBDII Civics. Each code requires different troubleshooting. Was your code P0505 or P1508/P1509?

 

the code is P0505

 

Is the idle speed too high, too low, or fluctuating between high and low?

 

it goes high and low. when it idles the A/C and the lights on the dash come in and out. like they fade and come back

 

With the warm engine idling and the intake/air cleaner removed, use your finger to cover the port in the throttle body leading to the IACV . Does the fluctuation in idle speed stop?

 

i'll have to check that when i get home from work

 

i forgot to mention that i just got a new A/C compressor put in and it only idles funny when the A/C is on

 

Was the compressor clutch relay wired through the ECU so that the engine will idle up when the A/C is turned ON?

 

i have no idea, how do i find out? i'm not to car savvy

 

what are the fixes for the p0505 idle control system malfunction.

 

are the parts expensive for the idle control system.