I have a F150 V6 2001. I have been having idling issues for awhile. After I drive it 30 or so minutes I can come to a stop the idling goes up and down from 600 rpm to 500 rpm and it causes truck to shake and almost go dead. Whenever I put it in park or neutral the idle goes to 800 rpm and stays..it does good out of gear! Ive cleaned the EGR , replaced DPFE , throttle sensor , pcv and replaced IAC. HELP!!!!