Long time reader, first time posting.

Like the username says, I've got an 03 F150 SCAB 2WD with the 4.6L(W) currently with 182,xxx miles. Lately, it has been stalling at startup. It cranks over fine, then idles down to ~500rpm (which now seems to be the idle speed, was previously higher, 600-800 range), tries to recover, then stalls. Does not give any trouble codes. It also sometimes hesitates when accelerating away from a stop. It seems to have good days and bad days. Today was a bad day, it might run fine tomorrow.

These are the steps I've taken so far:
-Replaced the fuel filter and ran a full tank of gas with a bottle of Lucas in the tank (my usual routine when I change the fuel filter).
-Checked the PCV tube for a vacuum leak (I had to replace one of the ends with a piece of heater core hose lacking the proper elbow about a year ago, so I figured it was as good a place as any to start).
-I've cleaned the IAC and checked it for function (unplugged it, idle got worse, plugged it back in, idle got better).
-Cleaned the throttle body, mind you not the best job, I haven't had time to remove it from the manifold and clean it thoroughly.

Any ideas as to my next step? EGR? TPS? Continue with breaking down and cleaning the throttle body? It may be important to note that the truck is now a second vehicle, if I put 10000 miles on it in the last year and a half, I'd be surprised. It has sat for 2weeks without being run a couple of times in that period.

Thanks in advance for any help!

*Update*

Finally got around to finishing cleaning the throttle body. One EGR port was completely blocked and the other partially blocked. Got the throttle body cleaned up and reinstalled. It idles a lot better, but I still have the stalling problem at startup. What do you guys think my next step should be?

 

Before dumping more money into things that could "possibly" work, take the throttle body and elbow completely off and clean them. You'll be surprised at how bad the ports in the back look.