Did a search but didn't see anything. 1989 f150 351 motor, cranks up ok with a little gas but I have to keep slight pressure on the gas to keep it running. When I put it in drive the rpms drop a little but will continue running with foot on the gas. After about 3 minutes of driving though it will idle fine as long as I need it to. Any ideas? Thanks

 

All of the older Fords that I have owned have all been cold blooded, meaning that they liked to be warmed up a little to run right. The biggest issue is to make sure you have no vacuum leaks and then have your carb choke system set up correctly. Your choke setup will make it like a new truck again.

 

It is always a good idea to start with checking for codes. Many times there can be stored codes without having a Check Engine Light on. Ford Fuel Injection » How To Run a Self-Test

Did this problem just start or has it done this for a while? When was the last time you did a tuneup with new plugs/wires/cap/rotor and filters?