After I opened up my exhaust with a flowmaster 40 series and larger pipe, my engine seems to be idling smoother. Its still slightly rough, but not nearly as bad as it was. Any ideas on anything else I could do to smooth out the idle? (Things I have done so far: Vacuum lines, fuel injector cleaner, new AC Delco O2 sensor, cleaned the K&N air filter, opened up the exhaust, new plugs, MSD Wires, Fuel injector cleaner every other fill up)

Are the terminals of your coils ok? i mean rusted/corroded. If so try and scrape all of it off with steel wool or a fine grit sand paper
You should check the resistances of your coils to see if there still good. The procedure and ohm values is in tech info.
When one of my terminals was corroded, i had a slighlty rough idle.

Easy. Rough idle is usually attacked with the #1 attempt at the throttle body. Get a new gasket, pull it, and clean it thoroughly, especially the IAC seat and shaft.

if you don't have a vacuum leak [the cause of my lopy idle], then make sure your MAF screen is installed, and not too beat up. Other than that, the suggestion to clean your TB.. will surely fix you right up.


-justin

Thanks, I will clean the TB next and see what happens.