saab 9000cse poor running

First Check socket to Air Mass Meter. Clean Air Idler Valve. Is the fault intermittent -> DI or possibly blown head gasket. DI problem develops over a couple of weeks until car stops! Is the idle high, any hissing noises? -> Vacuum leak from split hose.

Mileage? The more specific symptoms you can give, the better.

Sounds like you're are triggering an intermittent Limp Mode (assuming Trionic on your part) - and lord can that turn out to be obscure.

In my case, the car (1993 Aero) was triggering a whole series of different Check Engine Lights - all of which went away for days, weeks or months if you disconnected the battery for an appropriate length time according to the CEL - but which were never permanently repaired by replacing the suggested failure part.

As it turned out - it was a very slightly bent loom connector to the firewall Safety Valve beside the MAP sensor - a sensor that was replaced a couple of times. In my case that meant that every time a Tech would check the resistance on the Safety Valve (it should be very close to 30 ohms) and put the connector back together - it would run fine for about a week - then fail again for no apparent reason.

Given you have been to the dealer and assuming they have properly checked the safety valve and vacuum lines for correct parameters instead of just plugging in the scanner - I would start looking over the loom for suspect connections that feed the engine management computer(s).

It may well be that there is a problem with your Throttle Body or TCS system - but I now think that should really be the last stop in a rather longest trip through the wiring loom given my (and the previous owners) experience.

The can be many other reasons for poor running. I've had a few of those for my 9000 of same age, but not recently (or I would probably have written about it here). It would help if he can give more specific symptoms. The problems are often trivial and when you find the cause you shout: "Oh why didn't I think of that".

I guess the problem really comes down to when is a cigar actually a cigar, doesn't it? In the case of fully electronically controlled, interfaced and fired engine systems - you have to actually spark it up (so to speak) to find out.

In my case, I know in my heart that a long and fairly deep hand check though the electrical loom is going to consume a large part of the coming summer if I want to eliminate the basic loom from future bug hunts down the road.

I suppose that is to be expected given the 11 or so years my particular machine has been on the road. In fact, I think I can safely comment that it will be the challenge in the coming years for anyone who haunts the 'Utility Classic' end of the general automotive market on pretty much any make or model.

Actually - I think I'll start a new thread..

the head gasket is fine,when you drive it its great then for no reason the check engine warning comes on ,it then barely manages to tick over and it has a flat spot on the accelerater,if its in gear it ticks over if not it then stalls its an automatic which doesent help.it came on today the check engine light i lifted the boneet checked some wires out it then later on went out and drives fine again,i like the car its just an annoying problem i dont know what to look for or were to look any advice would be a weight off my mind,the saab dealer found the lambda sensor faulty and the wiring ,but they had it back 3 times its ran for 6 months no problems then back as it was before again thanks for any help,nice to know that people are willing to help

Yes - that is the limp mode kicking in.

If you stop and turn off the car, then turn the key to the on position without starting - it will flash the check engine light for a hint (although a vague one because it can be *anything* connected to the indicated faulty system):

2 flashes - Manifold Absolute Pressure sensor 3 flashes - Intake Air Temperature sensor 4 flashes - Coolant Temperature Sensor 5 flashes - Throttle Position Sensor 6 flashes - O2 Sensor 7 flashes - Adaptation 8 flashes - Purge valve 9 flashes - ECM fault

Get someone who knows how to use a voltmeter to check the Safety Valve on the firewall for (approx) 30 ohms resistance when the engine is hot. After that - you need to check for loose vacuum hoses all around the MAP sensor (rectangular block beside the Safety Valve on the firewall) and finally check all the hoses and wire connections around and under the intake manifold.

Really - the Trionic system isn't *truly* a standalone digital engine management system. It relies heavily on several electro-mechanical devices and sensors to feed it. In my own case, a number of these devices and sensors were replaced to no avail by myself and the previous owner - because the actual connector on one of them was simply misaligned and would present false resistances to the computer.

Hence my other thread..

The fact that it operates correctly again when you "check around the wires" and close the hood is interesting.

In my case, my shop (Halifax Autosports) and I finally clued to the fact that the machine would normally fail when Mrs Dexter J would be out and about with the kids (with all the long, concerned conversations about the wisdom of buying a 'Utility Classic' those sort of problems bring about).

.. :/ ..

Basically - when one of the kids hopped in the front seat and slammed the door - they would jog the connector enough so that it would momentarily loose connection enough to change resistance and thereby trigger one of many erroneous CEL codes as noted above. That was finally the tip that lead Mr Parson's and I down the right path. Basically - the computer and scanner were being feed incorrect data - which then lead to incorrect diagnoses by *several* shops and dealers down the line before and after I bought her.

It was maddening and remarkably expensive to finally figure that out - I can assure you. On the other hand, I have a lot of fresh sensors, intake and ignition components on the car that are likely to last for quite a while longer I suppose. I even have a spare DI cassette now.

Which brings up another piece of advise, never throw away a replaced part for a while after the repair - it may be that it was perfectly fine in first place.

Anyway - don't be afraid to poke around under the hood yourself, I actually set-up a quick disconnect on the battery to reset codes over the winter while we worked it through.