Got a 1997 F150 4.6L runs fine no missing at all starts up perfect. Cuts off when you slow down and quit giving it gas. Will idle fine if AC is on but if AC is off will not idle. Already changed the Idle Control Valve coil packs are good also. Any help would be greatly appreciated.

 

check the TB unit. It sounds like it is gummed up. Your idle on AC is normal. If you check behind the butterfly (seems like a lot of this, this summer) you'll find it all black and gummy. There are some holes (for air) that get clogged and don't allow good idle. You may have to pull it off to get a good thorough cleaning.

 

I wonder if the spray Sea Foam would clean it good enough will take it off tomorrow and probly and look at it.

 

Well the Sea Foam spray cleaner didn't work didn't even smoke. Now on to something else I guess.