My 1990 F150 automatic transmission almost stalls out at very slow speed when i quickly let off the accelerator. It also as a very small hiccup feel when i'm idling. Could this be the IAC??
It could be. It could also be a clogged fuel filter or spark plug issue. I would check both of those first, especially the fuel filter. When you are giving it gas it seems to be ok and when you let off quick it may not be getting enough fuel to keep going.
Let us know what you find. Good luck!
Yep what's the hard man very good advice also look for vacuum leaks anywhere you can find them sucking air
I put a new fuel filter in with new fuel tank and pump also professionally cleaned fuel injectors. I took off the IAC and saw that it was clean BUT! I did notice to small hoses near the IAC about 1/4 in in size that was off and plugged them back into near the IAC and followed where they go and noticed they go to some box looking thing kinda near the A/C and radiator. What the HECK are those small hoses??
the plug in ports where they go to looked clean and shiny. I plugged them in and started the truck and seemed to run OK but not totally sure what those hoses are?
More details on the hoses but the truck is a 5.0 and has 2 air intake hoses running to the engine an upper and lower next to each other. And the small tiny hoses i saw are literally next to the IAC. One small hose goes to the upper intake and one to the lower intake hose. My guess is that is where I might have had a vacuum leak but I'm still curious what those hoses are and what they are for?
Back with new news so those tiny lines are vaccum lines comming off the throttle body and they are right next to the IAC but I dont know what they are for.