High idle in Park and Neutral

I am the owner of a 1995 Pontiac Grand Am SE V6 3.1L automatic transmission with 171,000 miles on it. My car was idling high all situations so I replace the IAC. Now, the engine idle really high in Park and Neutral, but fairly normal in drive and reverse. If I let the engine idle high like this for too long the Check engine light comes on, but then shuts off as soon as the shift into drive or reverse. Also, recently my ABS light came on (it usually comes on after the vehicle is in motion). I replaced the wiring to the two front wheel speed sensors, but the light still comes on when making a sharp turn or most of the time just when taking off at low speeds. I don't think these two are related, but I thought I should mention both just in case. Thanks.

Check the codes.

I'd also check for vacum leaks. Might double check the plug and wires for the IAC and your MAF. :thumbsup:

Same with the ABS light, get it scanned with an ABS capable scanner.
If the wires are to short, while turning they can pull at the connectors or wires and cause troubles.