i did a tune up on my 1991 f150 acouple weeks back and sinse i did it it started having a rough idle but it drives perfect. just when you are idling it has a stutter to it. It also likes to go to high idle even after youv been driving it the same day.

 

Please give us details of this "tune-up" you refer to.

 

plugs,cap,rotor,wires,and fuel filter.....iv double checked the firing order

 

fix your vacuum leak

 

Did you correctly route the plug wires?

courtesy of Steve83

 

That is a valid statement as well. Did you have a high idle before?

 

yes it had the high idle before too but its only when you first start it up. it could just be going up to high idle but its weird tht it does it every time.

 

Verify your plug wire routing, check for codes by running the KOEO tests and CM check.