My '89 302 AOD Bronco has developed a hesitation from stop on part throttle. If I hit the gas harder it will surge forward and go fine. What should I do first. I am thinking another throttle body cleaning (did one 4 months ago). Timing is on the mark. Is this a sign of a failing TPS or dirty IACV. Idle is fine and idle fast warm up works fine and idle drops as it warms up to within spec. It is just an annoyance because it trick the tranny to upshift to second very soon.

 

BTT

 

EGR valve did this to me before.

 

You may need a new O2 sensor, the heated sensors run in a loop mode with set settings untill they reach 200 degrees. If your sensor is not heating up or registering the temp right it will cause power loss.