under the windshield washer mech (center, after the soundshield/firewall) is a black retangular box with a set of wires coming into it. Inside the box (which has a protective cover that can be pried off) is a circuit board. My rough idle was due to sliver crack in the solder- that as it heated up expanded and caused the solder to not allow the current and thus rough idle. You also have the idle control valve near the front of the engine- it's a grey/silver cylinder about 3 inches with a two wire prong and two air ports. Passenger side just in front of the air cleaner. That may be the culprit also. check plug wires, and plugs. Are you using 20-50 motor oil? you ought to.