95 neon rough idle w/amperage draw

[wanabehandymom]

I have a 95 dodge neon with about 170k miles, that idles rough when the radiator fan or a/c compressor comes on. A slight change in idle can be heard when headlights are turned on. I suspect the problem to be electrical because once in awhile it seems the headlights cut out for a split second. Also, it only seems to run poorly when there is a high electrical load on the car. The car doesn't studder on acceleration or normal driving speed. The battery, starter, alternator, fuel pump, air filter, spark plugs and plug wires are all new and I spliced on a new section of battery cable because the old was getting corroded. Intermittently I get very bad gas mileage (17 mpg) when I normally average in the low 30's. I don't notice a difference in how the car runs when it gets poor mileage. Both O2 sensors were replace in the last 3 years. Any suggestions would be appreciated.
:wall:

[Lugnut]

Sounds like your IAC (Idle Air Control) valve is defective. This might be verified by pulling codes.

Engine loads from the alternator (fan, lights) and the a/c will pull the engine rpm down. The IAC compensates to keep the idle steady. If the IAC is bad, the computer does not always know it, but may set trouble codes relating to poor idle rpms.

17 mph verse 30 mph. lol Sounds like you are merely running the air conditioner. ;)

[oldmedic]

Hey mom, lugnut's reply about running the AC all the time might not be as foolish as it sounds. If you run the windshield defogger/defroster alot you're actually running the AC compressor. Check to see if you're leaving it turned on. oldmedic