Saab: 1999 Saab 9-3 big problem, throttle position sensor, crankshaft position sensor

Question
Hi Jerry, I recently bought a 1999 Saab 9-3 (not viggen) and here's the problem I have.
Start it cold. Runs fine.
Let it warm up for 5-8 minutes, try to accelerate, the rpms freak out. They won't go above 2500 rpms. It just sputters and kicks it back down to about 1500 rpms.

I have:
1. Changed the direct ignition
2. Checked for air leaks
3. Changed the fuel filter
4. Changed the fuel pump
5. Put fresh fuel into it
6. Put new oil into it

Here are some other symptoms:
1. CEL codes read:
  Crank shaft position sensor
  Camshaft sensor
2. Sometimes the idle will drop to about 400 or 500 RPMs and have the car almost die.
3. Sometimes if I keep driving the car a little bit, the problem will clear up for a moment or so and then return.

Any suggestions? Need more info just ask, me and my dad have been digging and digging into this problem.

-Marcus

Answer
Marcus:

My hands-on detailed experience is limited to 1990 SAAB 900's and earlier. However, from your description, I would suspect that the crankshaft position sensor, likely a magnetic or similar device usually located near the damper pulley, but also possibly near the flywheel, is breaking down when hot,a common failure mode for such components. Can you get a "book" on the car that gives a procedure for testing that sensor? Have you located it on the car and examined it?
These are only general suggestions, but perhaps they can help.

Insofar as the possibility of a throttle position sensor being a cause, its certainly possible; a quick continuity/resistance test can usually check that out (with the aid of the HAYNES manual).