and have had the plugs,coil packs only 3 of em.,and throttle body replaced ,engine light on again,each morning at start it cranks like crazy,and i stop then on second time sometimes it starts,may take 2-3 trys but always starts...and if it fires up the engine idles really high then calms down,also after work each day after sitting,same thing,been to dealer,he replaced throttle body,and another mechanic replaced other stuff,after 700 bucks truck is still not running right,any clues? only 81,000 miles f 150 2005 4.6

 

I hate to tell you something to make you throw more money at it but, your problem sounds like the crank sensor is trying to die. This sensor is located very near to the a/c compressor in the timing cover. 1 8mm bolt is all that holds it in place. the cost is $40/50.00 at the dealer.

 

same issues only 2 years later! comes and goes have replaced 5 coil packs ON SAME CYLINDER PER THE PO307 CODE. all plugs.(misfire on 7) always...this will work for around 2 mos or so then C.E.L comes back ,to go on and off( with 7 misfire)...all about to give up HAVE 94,000 MILES NOW