Hi
I have a ford f 150 with 165,00 k runs well but i have a rough idol problem. At first it was only when i put the truck in reverse but now it is starting to happen when i shift to drive. it doesn't happen when on the highway or at acceleration. I changed both VCT'S and all 8 ignition coils. i bought the truck second hand but have no idea when the spark plugs were changed if ever??? i have also put in injection cleaner with a full tank. the problem is rough idol at 500 rpm (standing still in gear)
what are the possibilities???
Thank you for your input
69gto

 

Year please. I would check the Idle Air Control valve. 500 is too low for the engine to idle in gear. It should be around 650.