Pontiac Repair: 2005 Montana, switch problem, electrical connector

Question
When driving the RPM starting moving back and forth, and the the van start to run very bad. It then stalled and needed a tow. I had it looked at and they said the Ignition modals needed changing, that did not help. I had the local dealership look at it, with no luck.  It drive good and will stall once in a while putting it into gear.  The pressure on the fuel pump was 50 psi, and stayed at that when the van was acting up.  Not sure what to do next?

Answer
Hi
I am suprised the dealer did not help more.
I have had almost the exact same thing on a Montana van 2 different times.
There was an ignition switch problem once.
The other was an electrical connector, under the air cleaner box had a poor connection on one of the B+ circuits.
IF it is still under warranty, they HAVE to try to fix it (Unless it has a branded title)
I wish I could help you more. I'll TRY to go over my old records and see if I can find the EXACT terminal to check.
Until then
Good luck
I Hope this helps.
Pawl