i have a 1989 ford F150 4x4 with an 4.9 6 cylinder and when driving down the road at cruising speed it seems to have a pretty descent miss to it...i just bought it today and it seems to have a brand new tune up and everything looks to be good..any ideas as to what may be causing this?? timing maybe?? but if you step on it,it goes really good and doesnt seem to miss at all and keeps pulling strong..just when idling or at cruising speed..you cant really feel it..but you can hear it..it almost sounds like a carb..when it's really cold how it stalls and kinda pops..but it's fuel injected..i hope i didnt confuse anyone with this problem..any help would be great..
thanks alot..
mike

 

i read in my manual, that the engine actually gets the best mileage when it misses just a little bit and not to be concerned, as long as its runs smooth like you said. i don't know about the popping stuff though

 

depending on the mileage i would check the timing, and also maybe do a compression test.

 

it has 52,000 original miles..would that be the timing already??