I drive an '92 Olds 88, 206k miles. I’ve had an issue recently that when applying the brakes at a low speed, the engine will act like it’s going to stall out, the “service engine” and “hot” lights will flash, but then the car will resume regular driving. The “stall” will happen for a quick second, but the engine will resume running and I’m good to go. This doesn’t happen every day (once a week). I took it into the local shop a couple weekends ago, but no code was stored. Any advice, suggestions, etc would be greatly appreciated. Oh - don’t know that this would have an affect but ever since the weather’s been warm (and probably before that), the AC hasn’t been working. The guys at the shop say a busted controller head, but I’ve decided the “off” button and rolling the windows down works just as well for “air”. I’m a grad student at the moment so I’d like to find the least expensive fix, if possible. Any advice/help is greatly appreciated!
The lights are probably blinking on because the engine is temporarily approaching stall, turning the alternator too slowly for the moment to be charging the battery. But have the ECU scanned for codes anyway. AutoZone and some other parts stores will do this for free. Post teh codes here.
One real good possibility that comes to my mind is the brake booster. That’s a vacuum operated device the assist you in applying the brakes. It contains a diaphragm and some valves, arranged such that when the brakes are not applied vacuum from the engine is applied to both sides of the diaphragm, and when the brake pedal is pushed the back of the diaphragm is vented to ambient and the front becomes a sealed chamber.
The booster gets its vacuum from the engine. If the booster is bad, it could be allowing a vacuum leak to ambient as you apply the brakes.
Thanks for your reply. After I posted I had no more instances of “almost stalling” until literally this morning. And that was only when I had put my car into park while having my foot on the brake pedal.
I did stop by the local AutoZone and ask if I could see if there were any codes, however, they informed me that my car was too old for their universal reader for which the plug-in became standard only starting 1996.
I’m continuing to drive the car and it runs great other than the occasional “hiccup”.
One question - will the brake booster eventually go bad, and if so, will the car stop completely?
If my theory is correct, than the brake booster will not suddenly cause the car to stop completely. And your brakes will operate even of you lose the booster, the’ll just take more effort to apply. The brake system is hydraulic and while the booster assists you in pushing the pedal, loss of the booster does not interefere with the hydraulics. It’s an “add-on”, if you will.
But that assumes my theory is correct. The good news is that there’s a simple way to test it. With the car in park, simply push the brake repeatedly and see if it occasionally acts up. Attach a vacuuum gage if you’re able and watch for erratic vacuum drops when the symptom happens.
The way to operationally test a vacuum booster is
(1) with the engine off, pump the brakes a few times until the pedal hardens.
(2) while pressing the brake pedal, start the car.
The pedal should noticably soften.
Now, it is possible that you have some other cause, such as a bad Idla Air Control or something of that sort. The best way to try to solve it affordably is to start with a Haynes Repair Manual from the local parts store. It’ll guide you in checking possible causes and help you fix the fault when you find it.
Could also be a sticky torque converter that has trouble unlocking