2001 Rodeo Dies On Cold Start

I have a 2001 Rodeo LS, 2-wheel drive, 3.2 liter 4-speed automatic vehicle (engine specs 3165 cc, 6 cylinders, dohc multi-point fuel injection).

For the last week I have suddenly been having cold start problems. It starts, revs very high, drops down low, then dies after trying to stay running. It can take up to 6 starts (about 3 to 5 minutes) before everything smooths out and then it run fine for the rest of the day. I have had it into the dealer repair shop 3 times now and they said they cannot fix it. They have even consulted with engineers at Isuzu coporation. They are able to reproduce the problem, they just don't know what causes it.

Here is what they have fixed so far:
Replaced a leaky fuel pressure regulator.
Scan revealed that it misfires on all cylinders. (assume they did something about that)
Checked that it has the latest in PCM.
Sprayed the intake and replaced gaskets.
Replaced the fuel sensor assembly.

They left me with a recommendation to try a different brand of fuel and get a good fuel system cleaner and drive it for a couple of tanks of gas worth.

No body seems to know what is going on (even Isuzu). Any suggestions? - PLEASE!!!