Help: car stalls at low speeds

Factual Questions
1

I have a 91’ Saab 900 Turbo convertible, 109K miles. My car stalls during stop and go traffic and at low speeds (under 40mph). The car doesn’t easily re-start. It turns over easily, but doesn’t “catch.” The check engine light comes on, but turns off after the car re-starts. The dealer’s initial diagnostic couldn’t find a problem. Anyone have an idea what could be wrong?

I haven’t found a pattern to the madness. It happened 3x in one day in November, 2x in one day in Feb, and 5x yesterday. Each time the weather was cool and dry.

Thanks for your help!

P.

p.s. Thanks for all who helped me fix my plumbing! A little CLR and channel locks solved the problem.

2

My 66 Mustang used to do the same thing - it did seem to be a little weather oriented, because my dad’s friend the mechanic adjusted the idle because it was summer and we were running the air conditioning. I have no idea if this would apply in your case, but it does sound like a similar situation. We’d stall in parking lots. V. embarassing in a convertible where the pissed off people can see you!

3

I think the check engine light is supposed to be on when starting.

Clogged fuel line filter
O2 sensor gone bad
fuel pump/pump relay
But, diagnostics at dealer should have revealed the O2 sensor.

You have to jump back in and tell us about the general upkeep of the car: tune ups, oil changes, prior history.

4

consumer guide says stalling is common in SAAB turbos of this year and that engine comp replacement is the usual remedy.

5

I’d speed up the idle a bit & see if that works. But idle generally has a set speed you can check it at rest to see if its right. Its really a pretty easy thing to adjust on the cars I looked at.

6

Same thing happened to me - it would just die, always at low speeds. You could feel it start to die, and giving gas didn’t do anything. It wouldn’t restart immediately - for some reason you had to wait a few minutes. The mechanic couldn’t put his finger on anything definite, but I told him to replace the fuel pump. That did the trick.

7

My old Grand Prix used to do that. The mechanic unplugged some wires that went into the torque converter and it ran for another 100K before the ignition coils fried last month.

8

The dealer thought it could be the O2 sensor, but he said it was just a guess, b/c diagnostic didn’t reveal anything. Alternatively, he thought I could need a new airmass meter, but I had that replaced less than 2 years ago, and didn’t want to spend another couple hundred bucks on a guess.

I suppose I had regular tuneups and oil changes.

What does “enginge comp replacement” mean? That sounds expensive.

9

I assume he is talking about the computer… At least that’s what I thought when I read it. Ouch! This can be pretty expensive. It was expensive with my Subaru, and I imagine a Saab would be worse.

10

I did some quick searching and could not find anything regarding the computers on the 91 Saabs going bad.

I assume Philster was referring to this site. I could not find any information here either, maybe he’ll come back with a cite.