i have a rough idle and i did a tune up and its still running rough.. im out of options any ideas would help.. also some times it goes down to 7 cylinders but then go right back after i let off the gas.. its a 06 fx4 5.4 please help me

 

Did you tune it yourself or did your mechanic do it?

A tune-up isn't what it used to be. You need to be a little more specific.

Did you replace plugs or coil packs?
Did you check the MAF?
Any trouble codes?
Air/fuel filters?

What's the mileage on the truck?

 

I did it myself. I did the plugs and wires not the coils. I'm going to do the fuel filter this week

 

If you did the wires then I think you have the wrong forum. The 04+ do not have wires. They have a coil over plug system. If you have a 04+ truck and have a misfire I would try switching the COP with another cylinder and see if the problem follows.