hi i have a 1993 f150 with a 5.0 had the truck since july very familiar with the obs trucks to a point but this issue ive been having is very annoying ......it seems to idle high for like 5 or six minutes straight every time i start it up then it kicks down runs smooth then it starts to idle rough i tap the pedal it revs up kinda sticks a few seconds and idles up and down and once in a while the tranny acts up with it and after 5 minutes of driving the check engine light comes on and as soon as i turn it off the lights gone for a while again

 

Almost the same thing happens to me sometimes.... if I start the truck for the first time it will idle high ( around 2000 rpm) and then if I put it in gear it wants to stall sometimes un till I give it gas... it only does this when it's cold so idk what the problem is? Sensor maybe?

 

Idle issue sounds like both of y'all have a vacuum leak. Mine did roughly the same thing.

If you have a check engine light then you'll want to read the fault codes from the computer. That should point you in the right direction. Don't replace a part just because it was mentioned in a code description... remember the computer is telling you what is DETECTS is wrong, not necessarily WHY it's that way. If you do have a vacuum leak, you'll probably get a code showing lean readings from the oxygen sensor(s)... some people see that and replace the sensor when in reality the sensor was just doing it's job and the vac leak was the actual problem.

Transmission acting up could be a number of things. Get the idle issue fixed first, then worry about the trans.