4.0 SOHC problems

[fox.josh]

I have a 01 sport trac with 4.0 SOHC motor. I replaced plugs wires fuel filter and put a k&n cold air intake and cleaned Mass Air Sensor real good with contact cleaner and still it sometimes runs rough as in no power sluggish down shifts and bad gas mileage. other times runs great spin tires shifts firm and pulls hard. No check engine lights or anything on. Im stumped. I posted on the sport trac forum and didnt get any replies on the s ubject maybe you guys can help thanks

 

[davidg837]

I have a 01 sport trac with 4.0 SOHC motor. I replaced plugs wires fuel filter and put a k&n cold air intake and cleaned Mass Air Sensor real good with contact cleaner and still it sometimes runs rough as in no power sluggish down shifts and bad gas mileage. other times runs great spin tires shifts firm and pulls hard. No check engine lights or anything on. Im stumped. I posted on the sport trac forum and didnt get any replies on the s ubject maybe you guys can help thanks

I have the same vehicle and have a similar problem, I put in new wires, plugs, fuel filter and cleaned it up. Mine only seems to be a problem with low RPM. It runs fine and gets decent milage when I am on the freeways. I get 21.5 on the freeway and lucky to get 17 with city/highway combination.I was told that it could be a vacuum leak and can't seem to find one. I am not sure how you find the leak. If you know let me know.

 

[fox.josh]

mine i 4x4 and would love 21/17 in gas mileage mine is more about 17/15