99 f150 5.4l 175k miles. started skipping a couple of days ago, ran codes only get a P0300 general misfire. truck will down shift/over rev then sometimes will cut off while driving. will start back up after being switched off. Seems to be electronic, could this be the ignition module?

 

I have 99 f250 5.4 4x2 96000miles. 1000 miles ago I had similar symptoms. Began to get "limp home" mode from fail safe cooling and stalling upon deceleration or at idle. Additionally I had sporadic electrical symptoms such as: theft light would blink erratically, odometer would black out, got low oil press light, eng temp gage would drop to zero. Got various codes which some which cleared themselves (misfires, EVAP system, IAT sensor, CHT sensor) over 2 months. Here's what I found and did: chafed wire from knock sensor grounding to clamp=repaired, CHT sensor wire broken at sensor making intermittent contact=replaced, Throttle plate and body sludged... not closing and air hole blocked=cleaned, PCV valve needed replacing, found several vacuum hoses either total or partial colapse, one split and leaking=replaced. Replaced deteriorated hose from TB to EVAP purge solenoid on firewall.Cleaned MAF sensor. Replaced IAT sensor (one code). Idle air Control Valve sludged=cleaned, Spark plugs shot=replaced, tested fuel injectors= ok, tested COP's=replaced one, replaced gas filler cap, replaced fuel filter which was worst i've ever seen on removal. Took 3 days of my time, Haynes repair manual, 1 shade tree mechanic friend intermittently, info from various internet sites, and good fortune to find and fix it all. So far so good runs like new. I guess I'll keep 'er a while longer. Hope this gives you some ideas and inspiration.

 

thanks, it ended up being a coil pack #4 the worst one to get to.