This morning all of a sudden my truck started running rough. When in park it idles at about 500-600 RPM instead of the usual 800-900. When I accelerate from a stop it hesitates a little and then feels like the whole truck is out of balance. I did hear a couple of misfires (not really full blown backfires) but all I heard was two. There are no check engine lights on. My first guess was a fouled spark plug but I looked at the spark plugs and cannot even see the back two so I have not tried taking them out yet. Has anyone had this happen before?

I also thought maybe I got some bad gas so I bought an STP fuel system cleaner and put it in after I filled the truck up at the local Mobil. Could it be a clogged fuel filter? Mine was changed about 10,000 miles ago.

My truck is a '98 with the 4.6 V8 and has just over 40,000 miles on it.

Thanks for any help.

 

Hi Blue,
I had the same problem with my 2001 supercrew...it turned out to be a bad plug and coil. Had it changed about three months ago and everything was fine until yesturday...it has started again.

 

drpepper60,

Thanks for the information. I will have my mechanic check it all out tomorrow. I thought it might be something with my intake (Airaid FIPK) but I put the factory intake on and it did the same thing.

 

Hi Blue , Hi DRpepper , I also have a 5.4 2001 super crew that started this last week , I also thought it was bad gas and was disapointed after new tank of gas and injector cleaner , that it is still doing it, sounds like time to take her into the dealer for a full checkup!

 

I took my truck to my mechanic this morning and he just called and said that the spark plug wires are bad. He is upgrading the wires for me and putting in new platinum plugs.

I guess the crappy factory wires are only good for 40,000 miles.

 

Yup,

Id have to go with the plug wire and/or coils. One of those is not quite right. Could be a fuel filter, but i am a firm believer than unless you put something solid in your fuel tank, they just don't "clog up". Plug wires and coils can just go bad, not sure how the wires on a ford are, as i havent looked to hard for them on my mom'd expedition, but all it takes is a little nick or scrape on a wire to make them act up.

Good Luck.