Surging Idle, dies when idling and when stopping
Hey guys, sounds like I have a common 4.6 problem here. My car ran perfectly a couple weeks ago when I parked it. I went to drive it the other day and the idle was surging between 300-1500, the AFR was down around 10.1-11, and it'd die out after surging for a minute or two. It was also dying when I'd come to a stop with the clutch in or the car out of gear.
I had been having issues with it dying when coming to stops previously, and cleaning the IAC would help for a month or two. So I figured the IAC had finally gone completely bad, so I replaced it. Put in a Motorcraft because it sounds like the generic parts store IACs are junk, and it's still doing it.
It starts fine, high idles at 1500 for a few seconds, drops to 1100 for a few seconds, then drops to normal, then starts surging and the AFR drops. I've checked for vacuum leaks and haven't found one. Any other ideas? I'm thinking TPS possibly