About the ABS, see: http://www.sccoa.com/faq/Floyd ABS Article.pdf - might be a relay, might need an accumulator.
About the rough idle...could be one or more of several issues, from bad fuel/plugged filter/failed regulator, to vacuum leaks, to worn plugs/wires, etc. etc. etc. Your choice where to start if you don't know the car's history, so pick one and see what you find.
I'd do a visual on all vacuum lines, then check fuel pressure, then go after the plugs and wires. No codes is good info, none the less.
Might help to know if the idle smoothes out when the engine is at operating temp. Does it sound like a goose when you fire it up? Know how to do a smoke test to check for vacuum leaks? Throw a 13mm wrench on the nuts at the intercooler flanges to see if they're loose. Check the oil for water, check the coolant expansion tank for bubbles. Check the crank pulley/balancer for wobble. Check the firing order to make sure it matches this diagram:
