This may sound kind of obvious, but have you double checked your firing order? Ford numbers their cylinders from front to back with number 1 on the passenger side. Cylinders 1-2-3 are the right bank and 4-5-6 is the left bank.
You didn't say if it ran fine when giving it gas. If it does, I agree with the others on the IAC.
1992 Ford Bronco
E4OD- B&M Stage 2 shift kit
Full 3" stainless Bassani Exhaust
32" BFG's/stock suspension
"No replacement for displacement."
"Our lugnuts require more torque than most Honda's produce!"