Hello, I have 1989 Bronco II which is bucking, erratic idle, poor drivability, but only at start up. It runs and drives perfectly after it warms to operating temperature. So I need to wait 2-3 minutes on a warm day, but 7-8 minutes on a cold day. I'm not new to Fords, have a modified '96 Mustang, but this, my first Bronco just acquired Oct. 2019. I replaced the originsl injectors as one was leaking, but that made no change to to bucking start up. Tested the IAC, TP and MAP sensors, oK. Replaced the ECT sensor, but still no change. While working with a mechanic, discovered that unplugging the voltage regulator eliminated the bucking at start up! The B2 fast Idled up to 1,100rpm, then settled down, ran smooth, like every vehicle should, except I was not charging the battery. Thinking my problem was electrical I tested the battery at 11.6-11.8 key off. My battery is a good one. With cold B2 engine running, bucking, got 14.7 volts-too much charge as we want to see 13.25-14.25, right. Replaced alternator with a Driveworks brand. No change, still bucking at start up, then smoothes out after warm up 3-5 minutes. Some said the Driveworks brand was poor, so back to Advance Auto, they Exchange for a Carquest 80 Amp. Still no change. Not wanting to cut and crimp/splice wires again, I pulled the regulator out and replaced with a BWD unit. Still no change. I might add the charging voltage drops to 14.5 after warm up. The motor Smooths out and I can drive it. It is supposed to drop down a bit, thank goodness. But still charging too high. So phone call to bwd resulted in a spec sheet which says their regulator is based on a 14 volt system, with 14.7 nominal voltage. Not a coincidence I read 14.7 charging voltage at cold start up. I have not touched the white sense wire. The green ignition wire is at battery voltage key on eng off. Then the green wire voltage drops to 2.3 volts at start up. The B2 runs great AFTER warm up, 3-5 minutes, and a voltage drop down to 14.25-14-5. I am now thinking the 14.7 nominal charging voltage is not the problem, but the results of another issue. Can anyone help or experienced this anomaly?