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'95 Buick LeSabre starts and runs for a while, then stalls and dies

I’m driving a 95 buick lesabre, good condition, clean, 130k miles on it. 2 months ago the car started stalling and then it died. Took it to a shop, replaced all original fuel pump and fuel lines. Repeat this about 3 more times, all in all, the fuel pump, fuel lines, map sensor, mass airflow sensor have been replaced. Yesterday, the same thing happened. Took it to a different mechanic, he says he drove it for two days and couldn’t find anything wrong with it. Is there anything specific in a 95 lesabre that could be causing this? It drives fine for a while, and then out of nowhere it starts to stall, then the car dies and check engine light comes on. Gas is kept above half a tank due to winter conditions and the fact that it’s an old car.

Has anyone checked the engine’s temperature sensor?
A malfunctioning temp sensor can cause this exact problem by sending the wrong info to the ECM, thereby altering the fuel/air mixture that the engine needs.

Has anyone bothered to check the trouble code that was stored when the CEL lights up?

Have your mechanic check for a faulty Crankshaft Position Sensor.

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The crankshaft position sensor informs the computer whether or not the engine rotating.

If the computer loses the signal from this sensor, the computer see’s no reason to operate the fuel and ignition systems so the engine shuts off.

You’ll have to leave the vehicle overnight so when the engine is cold the mechanic can start the engine and then take a heat gun and point it at the sensor. If the engine shuts off as the sensor heats up the problem is with the crank sensor.

Tester

When the engine stalls and the key is still in “run” or “on”, the check engine light is supposed to come on. That doesn’t mean the computer has detected a fault, it’s just a test to show the light bulb behind it is working. If the CEL is on with the engine running, that means the computer has detected a faulty. But the computer can detect faults and not turn on the CEL too, so the first thing I’d do in this case is probe the computer’s diagnostic codes for anything active or pending.

If there’s no codes, active or pending, the problem is unlikely to be the MAF or MAP. It’s easy for the computer to tell if they are working at least well enough to run the engine or not. It’s not possible to tell via the internet what’s wrong, but it is probably something easy to fix. The problem is that it might not be equally easy to diagnose. That’s why you need to use an experienced mechanic who commonly works on Buicks. Otherwise you’ll find you can quickly run out of money replacing parts willy-nilly, and before you find the actual problem.

My guess is either a fuel system or ignition problem. There are basic tests a mechanic can do to tell which system is causing it, then they can go from there to find what part is bad. But unless there are trouble codes in the ECM memory or they happen to visually see something amiss during a look-see, they’ll have to have the car in the shop when it is broken. What that means is you should be prepared to tow it in to the shop next time it dies like this.

I like the crank sensor is bad. They tend to fail when warm. Keeping the tank half full is not necessary. It allows moisture to form in the tank. Ethanol absorbs water and that’s not good.

To see if the problem is due to a lack of fuel or an ignition problem simply spray a small amount of starter fluid into the intake when the trouble happens. If the engine doesn’t respond to that then look for an ignition problem, like the crank sensor issue that was mentioned.

Coil pack and ignition module problems were common back in those years on GM cars and would cause problems exactly like the problems you are describing. If you let it sit for a 10 or 15 minutes does it restart and run normally? One bad coil in the coil pack can cause the ignition module to shut down until it cools off.

Have either of these mechanics had the car in the shop with test equipment hooked up to it while it was stalling? If so then they are missing something obvious.

If not, next time ask that they hook up fuel pressure gauge, spark tester, and a fully capable scan tool and leave the car with them so they can drive it throughout the day and try to duplicate the problem. Since the problem is so intermittent in nature you may need to leave the car for a few days.

The crankshaft sounds like it could be a good possibility. The only days it has ever happened is during snowy traffic jam mornings, so my car has been running for quite a while. It would make sense that as the car heats up like this that it could fail if it’s faulty. I have also been talking to my mechanic buddy, he said Buick has had problems with crankshaft and ignition switches. I’m going to a Buick deslership to confirm if it falls under that campaign of bad ignition switches, but I will also have the crankshaft position sensor checked out too, im thinking it has to be one of those as almost everything major fuel related has been replaced. Thanks for the replies.

Did you find out what the problem was? My Buick is doing the same thing.