2 different problems

I just bought my first truck, 1991 F150 5.0 automatic 4x4. I am having problems when I start off from a dead stop. When I press the pedal there is a hesitation. I then give it more gas getting still more hesitation until it finally takes off. It feels as if it is missing.
I have replaced plugs and wires with Motorcraft brand. I have also cleaned the idle air controller, but still get the hesitation. When I probed the IAC line coming from the computer I got 12.5 volts when it says it should be 10.5.

I am also getting jerks from the transmission and it does not shift smoothly.

I am very excited about finally getting a truck, but this sure has taken the fun out of it.

Also is there any adjustments for the tranny for this year. Looking through the manual it appears to be the E40D. The manual is a Haynes. Are there any better manuals?

 

First off, welcome to the site. There is a great number of awesome people here to help with almost every possible situation.

For now I would leave the tranny alone till you have the engine running correctly. Your tranny issues could be related to the engine not running correctly.

I would try cleaning the throttle body and check to make sure the throttle position sensor is reading correctly.

When you post next time, please include the mileage on the truck.

Have Fun & Keep on Truckin'
Dean

 

It could also be your injectors, or a clogged fuel filter, but I'd lean towards the injectors.

Dean is right, though, that it could very well be your TPS. See what it reads at idle, and how smooth it transitions to WOT.

Take care,
~Chris

 

Start with the basics. How's your timing? What are the KOEO and KOER fuel pressure readings for each tank?

Try not to start throwing parts at her until you've done a few checks. Report your checks back to the board and I sure some of us will try to give some more ideas.

Good luck.