There has been lots of discussion on this forum about vacuum problems...try a search.

If you are lucky, one of the lines may have been pulled off when the oil filter was last replaced...the lines going to the passenger compartment are nearby. You can disconnect the lock system lines by pulling them loose from the 1X2 check valve and plugging the check valve side. These lines are solid yellow and yellow with stripe. The solid yellow one goes to the driver side door lock valve, and the striped one goes to the accumulator tank (stores vacuum to allow several lock/unlock repititions). If the engine shutoff works, and the car is shifting ok with these lines plugged, the problem is in the locking system...likely one of the door actuators.

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