2000 Buick LaSabre - engine stops when car is coasting



Going any speed down hill. Coming to a stop light or stop sign. Happened several times at 70 in cruise control. No codes or checks. The Buick people in Branson, MO and Frederick MD had no luck. Last time (after 10 days with no shutdowns) when coming to a red light. Next day stopped 10 or so times in the space of 100 yards. Each time I put the transmission in neutral, hit the starter and the transmission back to drive.


Strange stalls always make me think of idle speed control. This is a device which bleeds a small amount of filtered air into the throttle body to adjust the idle speed to the correct rpm’s. They get sticky and stop maintaining idle speed when they get older.

If your car has a tachometer, watch it (if you can without danger) and see if it drops way down any time you let up on the throttle.

And/or if you are not in serious traffic, try driving one foot on the throttle and the other foot for braking, temporarily and see if holding the engine idle speed up around 700 rpm prevents engine dying.

On the other hand, sticky idle control also may cause stalling when starting the car. So, this is just something to eliminate.


Still dying in cruise control would seem to eliminate that, wouldn’t it? Oh, well.


In Branson, MO I added a can of dry-gas thinking there may be water in the gas. On the return trip from MO to MD I used 93 octane. In MO it quit doing 75 in overdrive w/cruise control. I went to 70 in third gear w/cruise control. It tried to quit in 3rd gear but recovered on its own. After 20 miles in 3rd I went back to overdrive and no problems until after I was home in MD for about 10 days (see initial message). The fuel pump and filter assembly was replaced 2 months prior to trip to MO.




The car has 161,500 miles on it. Appreciate the response. Will check it out.


Replaced crank sensor. Not the problem. 2 days later drove the car about 15 miles. It was parked for 3 hours. When started it was putting out smoke and would not idle. I could hold it at 1500-2000 rpms for a couple of seconds and it would stop. tried for about 5 minutes - no luck. Had car towed in to Buick. They said there was a “mass air” code in the computer that was zero time ago. I told them the car had not been started since the problem. They started the car and it ran normal. This is the same thing that happened in Branson, MO. They are going to clean the wires on the mass air unit and we go from there.


The fuel pressure regulator could be a possibility.


The Throttle position sensor also a possibility.


This was the first item replaced when the problem started in June. Tony


The complete fuel pump and filter assembly was replaced about 3 months before the trouble first appeared.


They removed the mass air sensor today (8-24-07)to clean the wires, etc. When they removed the mass air sensor it appeared that it was hit by something and the plastic housing was cracked. There is the possibility that moisture was getting into the unit. The unit was replaced. All of the maintenance on this car from day one has been done at a Buick facility. I’m ready for the problem to go away!!


The fuel regulator is not part of the fuel pump,is located under the hood, and I think it regulates off engine vacuum. I know my 2000 Impala LS had it replaced at no charge under a recall, and I believe your car uses the same part.


The fuel regulator is not part of the fuel pump,is located under the hood, and I think it regulates off engine vacuum. I know my 2000 Impala LS had it replaced at no charge under a recall, and I believe your car uses the same part.


Another possibility is you may have gotten a new defective fuel pump.


Will check my ALLDATA for a recall on the fuel regulator. I’ll check my paper work for each visit also since I know some recalls have been applied. A defective fuel pump crossed my mind a couple of times!!
Appreciate your input/suggestions. Thanks Tony


I bet I know the answer. My Mother has a 2000 LeSabre and she encountered the same problem. She was put throught he ringer by an independent garage and two Buick dealerships replacing the fuel pump, fuel pump relay and the main computer. Finally, it happened on a trip close to a Cheverolet dealership. They found a loose wire behind one of the taillamps of all things. That was about 2 years ago and no problems since.


Does this happen when your foot is on the brake? If so, you may need a new brake booster. If it is leaking when your foot is on the brake pedal, the vacuum loss could easily be enough to stall an idling engine.


Fuel regulator replaced per recall


The majority of time there is no braking involved.