Hey...my car is falling apart...

I own a 98' civic with 180000...in all honesty the car has been great to me. I just replaced the compressor, clutch, drier....pretty much the whole ac system. (That had nothing to do with anything but) Now I have a check engine light. The codes are P1362 & P1509. 1362 is an ignition system failure or misfire...the second is IAC circuit failure. The idle is constantly dipping. It idles right around 1500. Here's the weird part...as soon as I turn the a/c on the idle smoothes. (Told ya it was weird) Before I dump more money into the car I need some advice. If anyone has some expertise they could lend me it would be greatly appreciated.

P.S.
Originally there was only one code...P1362...I tried to fix this problem by replacing the spark plugs, wire, dis cap, and rotor. Nothing...then I gave up and took the probelm to Pepboys. Thats when the second code popped up. Are they related or do I just have bad luck?! Could the one code be causing the other...? Ok I think I am done typing...

Chris