my 2007 F-150 with a Triton 5.4 is slow to respond to the accelerator and even stalls sometimes when I need quick response. Is it he spark plugs? they're original, 148,000 miles

 

 

100k never was a good idea . Marketing hype-- bet a lot of ford engineers were biting their tongues .
I still hope this poster has good luck getting them out . It is going to take some study on here for him to learn all the stuff he needs to do .
Buy the lisle plug extractor and study the ford TSB on this for one thing ..

 

sorry double post -- I guess the new program on here doesn't catch this like the old one . .

 

Before starting the job, run a stiff dose of Techron or Seafoam through it to remove as much carbon as possible. Removing the PCM helps with access to #3 & 4. I also suggest a telescoping extension so you can get at exactly the right elevation to have your ratchet handle 90 deg. to the socket. It's imperative that you keep the torque vector perpendicular to the plug and the socket axially centered on the plug. If you get to honkin' off at an angle, you WILL break plugs.