Saab 900 - random stalling

I have a 1998 Saab 900S (automatic transmission) that we have done a lot of work on recently. The Check Engine light is on, and no computers will sync with the system to pinpoint the problem. The actual problem is that the engine stutters and sometimes stalls when you accelerate. It goes fine down the highway, it’s just getting started that’s a problem. It doesn’t always do it though – more when the engine is cold, but still frequent with a warm engine. It overheated a few weeks ago and leaked coolant inside the engine – thinking some wires might have gotten wet. Have put 300 miles on it since, but the car hasn’t come out of it yet. Any advice??

If no scanner can get a code, the PCM may be shot. Consult the manual to see what the next step is when MIL is on and there are no codes.

It overheated a few weeks ago and leaked coolant inside the engine?

Do a pressure leakdown test on the cylinders. It sounds like you’ve blown a headgasket. That won’t typically cause stalling all by itself, but it sounds like you have much more serious problems than just stalling.

“It overheated a few weeks ago and leaked coolant inside the engine”

Did it leak coolant inside the engine, or inside the engine compartment?
There can be a major difference in the probable causes and the likely outcomes of overheating, depending upon which type of situation it actually is.

As my friend, mountainbike correctly pointed out, if there is coolant present in the cylinders, that indicates a blown head gasket with resulting VERY high repair costs. On the other hand, if the coolant merely leaked inside the engine compartment and soaked some wires, that is not anywhere near as serious or as expensive to fix.

Of course, overheating is not a good thing, and you do need to find out why the engine overheated in the first place. Bear in mind that it is possible that the overheating was caused by a breached head gasket. It is also possible that the overheating warped the cylinder head and has resulted in a breached head gasket. You really need to find the cause of the overheating and you need to determine if there was engine damage as a result of the overheating.

I think you have to begin to assess how much more money you are willing to sink into this car, just so that you are prepared to make a rational decision if and when you get the next high repair estimate.

Thanks for the info. It overheated and coolant leaked within the engine compartment, not the actual engine. My dad seems to think some wires are wet, which is causing the engine to be less responsive during acceleration. He is having a hard time pinpointing the exact problem.

While this seems like a better situation than it originally sounded like it was, you have to bear in mind that many modern engines do not take well to being overheated. So, it is entirely possible that you now have a warped cylinder head and a breached head gasket.

I would advise you to do a leakdown test to verify the condition of the engine. Also carefully monitor the rate of oil consumption and coolant consumption, as well as looking for traces of coolant in the oil (it will look like a chocolate milkshake), or oil in the coolant (there will be a dark, oily line in your coolant overflow container).

Good luck!