been having some troubles with my 94 f150 5.0 its been running real ruff at i replaced the iac it started to run better but has acceleration and occasional miss. i ran some codes and came back with this 172(runnning lean) 538(insufficiant rpm change) 632 (overdrive cancel switch)

 

You may have a fuel pressure problem, put a pressure gauge on it and see what you get.

 

Got low 30's?

 

Your fuel pressure should be between 30 - 34 lbs at idle.

Speaking from experience, the first place I would check when dealing with drivability problems, especially low RPM problems, would be looking for a vacuum leaks on the plastic vacuum lines coming from the vacuum tree on the intake. The leak can cause a lean code, that or thermactor tubes (on the back of the heads on a V8) being rusted out.

 

Turns out the o2 sensor was out who wouldv guessed? But now it idle's real high in park

 

try disconnecting the battery for half hour