I have been cursed with this problem since last October. I have replaced the fuel pump, fuel filter, fuel pump relay, inertia switch, ignition switch, MAF sensor, IAT sensor, and crankshaft position sensor and was still having the same problem. I FINALLY figured it out. One of the wires in the wiring harness on the inertia switch wasn't locked in place anymore and had fallen about half-way down the connector but never came out. This is always why stalling was worse with a passenger, since it is in the passenger floorboard. I glued the wire where it couldn't come out and it is doing fine.
Tuesday, June 22nd, 2010 AT 6:35 PM