97 f250 OBS when you start it up it idels fine but when you take off it surges up till 35 mph if you stay over 35 for over a min or two the low speed surging goes away till you shut the truck off. when it does surge the rpm drops by about 1,000 rpm. it feels like your pumping the gas and will keep doing this till you get over 35 mph.

 

Have you checked it for codes yet?
Also more details would help what motor what trans ect..

 

sorry 5.8 auto 4wd how can i pull the codes the check light is on but cant fig how to pull them not use to ford computer

 

Edit: Whoops! I just noticed that you said it was a '97. I think by then they had shifted to the OBD-II type of diagnostic system. So you can go get a OBD-II scanner for yourself, or take the truck to one of the major stores like Autozone, O'Rielly's, etc, and see if they have a code reader which you can use.

The following is specific to EEC-IV systems:

You can pull codes manually yourself. Check here for instructions:
Fuel Injection Technical Library » How To Run a Self-Test

Or you can buy an inexpensive code reader which makes the job a lot easier: