The truck runs fine now

Turns out the existing key was causing intermittent starting problems. Sometimes it would "communicate" w/ the ignition, many times it wouldn't. So they activated and programmed my second key and told me not to use the original key any more to start the vehicle but that I still could use it just to lock and unlock the doors.

The second finding was indeed the fuel pump.

Gilly, maybe you can set me straight here, but the truck had to go back a second time. The first time, they fixed the key situation and installed the factory pump that I brought with me.

They probably did not do a thorough road test because when I came to pick it up, it fired up but was stalling terribly.

They took it back in for another day and replaced the fuel filter this time. That fixed it for good.

I thought the fuel filter was an integral part of the pump assembly. Is there a second filter?

Anyways, I'm lovin my ML again.... warts and all!

Turns out all your diagnoses of the problem was right... they just hit me all at the same time!

Thanks, guys!