'91 Buick Les LTD stumbling/stalling

[avatar307]

How about a vacuum leak? Have you checked all your vacuum lines to insure they are in good order.

Before all the extra sensors were added to engines, vacuum lines controlled a lot of functions, 50% of the devices controlled by this vacuum could feasably cause stalling, rough idle, etc.

I'm the 1991 has plenty of vacuum lines to check, at 180,000 miles, I would just replace all the vacuum lines. The vacuum lines on a 1991 should control the EGR and fuel pressure regulator directly, as well as the transmission modulator, EVAP canister, and provide vacuum to the brake master cylindar.

I'm replacing the couple rubber lines on my 1995 today in fact, as they have completely degraded. I'm not even sure vacuum was being provided to fuel regulator any more. However, on my 1995, most of the rubber lines have been replaced with PVC tubing, which has stood up to heat and time a lot better. My environmental controls are still recieving the vacuum needed to work despite the ugly hose, but the fuel pressure line was just barely hanging there. Quite disturbing.