my 1991 f150 xlt started running rough on idle and going down the road.Engine light comes on, loss of power, i changed the fuel filter, air cleaner & checked for vacuum leaks, I can't figure it out . I am not a very good mechanic. if anyone has an idea i'd be grateful. Thanks

 

If the engine light came on, you need to read out the codes. If you are not a very good mechanic, I'd recommend you take it to someone who is.

I would suspect it's time for a tune-up - plugs, wires, cap, rotor.