PontiacBonnevilleClub.com

The car stalls when im coming to a stop/slowing down hard/making a turn. When im about to approach a stopsign/light, if i throw it in neutral and coast to the stop...the car does not die. When i am slowing down to make a turn, the car dies and i lose stearing....my battery light comes on as well. If a car slows down fast in front of me... the only way to hit my brakes without stalling is throwing into neutral first.

-only way to keep it from stalling is throw the car in neutral when braking... I only stall in neutral if im making a hard braking turn?? Any Theories?

Check the vacuum lines in the engine compartment for leaks, disconnected or bad hoses, and broken fittings. Especially check the vacuum lines and fittings to the power brake booster, and also check the booster itself to see if the diaphragm is holding vacuum. If the vacuum diaphragm is damaged, there could be a vacuum leak every time you apply the brakes - possibly large enough to stall the engine.

To check the power brake booster for leakage upon braking, you can disconnect the big vacuum hose to the booster and plug the end of the hose tightly. This will leave you with NO POWER BRAKES - so be very careful when and where you do this test. You will need to press the pedal with much greater effort to bring the car to a normal stop. Test the pedal effort in a safe place with the car going very slowly to get an idea before attempting to brake from normal speeds. If the stalling problem goes away when the hose to the booster is plugged, you can conclude the booster is bad.

Similar symptoms can be produced from a lockup torque converter that does not unlock, causing the car to stall upon stopping.

Does it do it in the lower gears where the lockup feature is not present? If it doesn't cut out, the converter is the problem.

Used to see this problem on GM vehicles. The overdrive lockup would not unlock. There was a plug on the top on the tranny we could disconnect to temprarily solve the problem.

I had the same problem...TCC lock up...1800 tranny rebuild later it worked fine..


Srry... Have a shop or Autozone pull any stored codes to diagnose.

Yes i have had the TCC code come up before....im thinking thats whats causes the car to Buck inbetween gears, which has not been happening recently....yet this is a different problem im thinking with the stalling............i just had autozone run a code and what came up was the 'Mass Air Flow Sensor"........ could this be a solution for my car to stop stalling??
Thanks Guys

You can try disconnecting it to see if the problem goes away. The computer is supposed to go to a default setting when it is disconnected, but I've had some cars that wouldn't run at all when it was.

...so disconnect and reconnect the sensor, then try to see if the same problem exist?...

..or disconnect and try running without the sensor connected?...

dosent make sense or i dont get it, if it was disconnected while trying to drive, wouldn't it act the same as if it were connected being bad

The best way would be to start the car, then disconnect it. If it stays running, try driving it around and see if the problem goes away.

If the sensor is bad, it can send a varying signal to the computer even when conditions are static. That can confuse the computer. Disconnecting it will have the computer go to default settings, and use other sensors to calculate the air/fuel ratio.

I disconnected the sensor....the car still ran, then i drove it disconnected. then after driving about 20 miles...it stalled again,when i broke or turned into a parking lot, being disconnected. im taking it to a dealer to have them diagnosis it. I dont want to spend $90 to tell me its a battery. Does anyone think this could be a battery. It wouldnt start once after sitting for a day<ONCE>....I have had it sitting for more than a few days...I am going to start it this evening and take to a dealer.
ANY OTHER IDEAS?...please, so i dont have to spend 90 bucks...........unless this might be the only way...some are saying it could be a hose leak.

We have seen random stall problems caused by electrical power issues, specifically, bad grounds, corroded battery cables, or corroded connections. A bad battery or alternator could be causing your problem. Archon has some experience with this on the 2000+ battery ground cable under the rear seat. I'm stuck back in the 92-99 years and probably will be for a while.

i ran my car without the MAS and it didn't like idleing at all it almost stalled when i would come to a stop i wonder if the sensor could just be completely bad

you really should start your own thread, but when you unplug the MAF and the car runs worse, that usually means the sensor is working

bonnevillain wrote:you really should start your own thread, but when you unplug the MAF and the car runs worse, that usually means the sensor is working

you misunderstood, i meant that i since his didn't change at all when he unplugged it maybe his sensor is just completely bad i was trying to help not threadjack

so since i unplug the sensor, and it almost seemed to work better for a few miles, Not plugged in, then started stalling again... that means if it runs better unplugged or about the same when plugged in, i have a bad sensor? I dont want to take it to the dealer, but i dont want to but a sensor and be out the money if that did not fix it ... ???

sorry for the questions guys

i'm just guessing the gearheads know better then me i dont want to confuse you

If you are concerned about a power problem, clean up all the power connections under the back seat, and to the under-hood fuse block. While under the seat, remove the bolt that connects the negative battery cable to the floor pan. Clean that bolt up well, as well as the threads in the floor pan. That bolt can get quite rusty.

Did you ever check for a vacuum leak at the brake booster, or along that line? How about other vacuum lines? The T under the supercharger snout, or the multi- port on top of the supercharger. While the code says MAF (do you know what the actual code was) there are things, such as vacuum leaks, that can cause the MAF not to read properly.

This weekend when Harofreak00 and I were working on my car, he was running the wiring and plug wires and everything under the snout of the S/C and knocked that Vacuum T fitting off, and the car stumbled really bad, and almost stalled out. Also, when I first removed it, the T broke, so I had to get a new line for that. It's called the Vacuum harness. Those fittings get really hard and crack, and that could be a cause of your leak, because at idle is when you're pulling most vacuum, and your power brakes pull vacuum as well. Check all vacuum lines and fittings. I'm sure there's a diagram in Techinfo, and if not, someone can post one from an FSM.

hey thanks, im gonna check these out....hey since the car wouldnt start a couple times, im assuming i need a new battery.... can i buy a battery that is used for a regular Bonneville.....cuz walmart has a regular bonneville but not for the ssei....i just dont want to spend $130 at autozone....any ideas on a battery or can i use a regular bonneville one?

The regular battery will likely be too small physically for the vent tubes to connect properly, and will also have less CCA. Most brands should do fine, but be certain that you get the proper one for you car that allows for attaching the vent tubes so that the gasses are vented outside.