Do you adjust the min idle speed & TPS when the engine is hot or cold? In the past, I've gone and set the min idle so that it's 500 RPM in drive with the IAC unplugged. (hot engine) Put it all back together and the alternator won't kick on idling at 500-550 RPM. The alternator needs to see 700ish RPM to kick on. This is trouble particularly when the car is fully warmed up and it's hot outside. Sitting at traffic lights etc. When the car is cold, it idles high enough that the alternator is on. (Volts reading upper 13's, low 14's) So this afternoon, I set the min idle at 650 drive, 750 in park. Hooked the IAC back up. Adjusted the TPS to .545 volts. Start the car up and it wants to idle at 1200 RPM in park. Coolant temp is at 185-190°F. Why can't I get this right? I did have the car running with the paperclip in the underdash socket at one point. Maybe I need to unplug the battery and reset any issues??? For the moment, I'm letting it cool down to tackle later on tonight/tomorrow morning.

I have the same exact problem im trying to work out, and im in houston too, im on the north side of I45 near Spring

*face palm*

I think I figured out why it would either bog or rev too high. I checked the motor oil dipstick. It was sitting right on the "ADD" line.

Re-did the unplug IAC plug...set the min idle.....plug the IAC back in.....set the TPS voltage. All is good now.

I spoke too soon.....Today it stalled at 500 RPM on initial start. Then after 2 more tries, ran slightly rough at 1000 RPM. After it was warmed up to full operating temp, it wanted to idle at 1800 RPM in park or neutral. It darn near took both feet on the brake to keep the car stopped at red lights.

Occasional low power during acceleration. Like running with a choke on or something like that.