My '96 Maxivan with a 360 and OD transmission has low power when climbing passes (9500 ft elevation +) where i live in Colorado. The van barely creeps up these passes in 1st gear. There are no error codes in the system. Any suggestions on what is going on. This van is brand new for me and was formerly in Texas. Is there any adjustments that I need to make for high altitude. My home is at 7300 ft elevation just outside Durango, Co.