1991 Saab 900 with 120,000 miles. While driving the engine just cuts out without any warning. The following parts have been replaced: throttle position switch, ignition module, fuel pump. The only code the Saab dealer can read is “mass air flow sensor - mixture too lean”. Other suggestions to check/replace: oxygen sensor, crankshaft angle sensor, fuel ECU, ignition switch, ground wires.
Help! I don’t want to throw more parts (Saab parts are very expensive) at this car. Has anyone else experienced this problem and what was the solution?
The following parts have been replaced: throttle position switch, ignition module, fuel pump. The only code the Saab dealer can read is “mass air flow sensor - mixture too lean”. Other suggestions to check/replace: oxygen sensor, crankshaft angle sensor, fuel ECU, ignition switch, ground wires.
That is an impressive list of parts to throw at this problem. The one thing I find interesting is that I don’t see the MAF or it’s sensor on the list.
I’m assuming here the car does not quit completely, but coughs and sputters momentarily before becoming normal again, or as normal as a SAAB can be?
(Just kidding. I’ve owned, and do own, a SAAB 900 along with being an ex-SOB tech (sic)). 
If this is the case then it could very well be the MAF sensor given the code being set, although a failing distributor Hall generator could also cause those kind of symptoms.
I will also point out that even things like spark plugs and plug wires can be intermittent in some cases and may misfire on an irregular basis.
Since MAFs are usually expensive you might consider a used or new one off of eBay. There is an eBay seller who sells used SAAB parts (located in Colorado) at extremely reasonable prices and guarantees them.
I’ve dealt with him several times and he’s a standup guy. The eBay ID is prohrman if you’re interested.
Other eBay possibilities include this:
http://cgi.ebay.com/ebaymotors/New-Air-Flow-Sensor-88-90-Saab-900-89-92-Saab-900-MAF_W0QQcmdZViewItemQQcategoryZ33557QQihZ020QQitemZ300128920087QQrdZ1QQsspagenameZWDVW
Dirt cheap IMHO. Hope some of that helps anyway.
Thanks for the suggestions.
When the engine cuts out, there is no sputtering or bucking, the engine just cuts out. The only way to tell is that the tachometer drops to zero. Sometimes you can shift into neutral and restart the engine, sometimes not. As usually happens, when it’s at the mechanic’s or dealer’s shop, it won’t stall.
I’ll look for a used MAF sensor as the Saab dealer wants $410.
Thanks!!!
I’ll have to think a bit more about this one. Since it just flat quits with no sputter I would be inclined to think the problem is not MAF related. Back later.
I’m still hazy on this one but considering the symptoms I might be leaning towards the Hall generator in the distributor or possibly the electrical part of the ignition switch (especially if the key has some significant slop in it) rather than a MAF.
It’s possible that you could have 2 problems and the MAF code is unrelated to the cutting out problem.
If it were me I would connect a vacuum gauge to the manifold and see what’s going on with the manifold vacuum. If this vehicle is turbocharged, it’s possible that the turbo overboost switch could be sucking air and causing that MAF code.
Those ignition switches between the seats seem to take a beating due to that pendulum affect from the lockout bar and all of the cookie crumbs and coffee getting dumped on them.
Hope some of that helps anyway.
Thanks OK4450. Sorry for the delay in responding as I’ve been away.
My 900 does not have a turbocharger so I’ll focus on the Hall sensor and ignition switch.
Thanks for the suggestions!!
Have you had any success with these suggestions. I have a 98 saab 900 that is doing the exact same thing. complete loss of power for no apparent reason. ignition goes, power steering goes, and you gotta just do your best to get pulled over without getting killed. like you said, sometimes it will start right back up, othr times it wont. when it wont and i get it towed it wont act up for the guys at the shop. ive had a shop driving it intermittently for 2 weeks now and it wont act up. they are now suggesting we take a stab at replacing the ignition components to the tune of 630$. it sounds like that did not work for you. i am so ready to offload this car and get a honda that runs. any help would be appreciated. chad