Went with 20/50 oil, since I could replace ALL the sensors, switches, relays, etc, and still have the problem. Hopefully the alarm won't come on again.

Also had my IAC valve cleaned out... they said it was quite carbonated. Car runs a lot smoother now. Didn't change the brakes since they are still 50%, but now I will have a complete set minus front rotors for a 100/A6.

Seems ready to drive again... going to leave probably Wednesday for about 2,500 miles.

I thought I was using some hard core oil when I started using 15w50 ;)

Hope it works, the idea of sensors on cars to let you know when something goes wrong is good, but when you don't know weither the sensor is bad or there is something else wrong it gets confusing.

I have been thinking of cleaning my IAC, don't really have ruff idle but after 80k miles I am guessing it probably needs it. Does it make a difference worth the effort or money?

Well I'm positive that there is no problem with the car, just perhaps a faulty switch (sensor would cause the light to go off again, as I'm told). So it could be any one of three switches, for starters, which cost $5-$85 each... not a big deal but, I can't get them for a couple/few days, and that might not even be the cause. Was the mechanic's recommendation to switch to a 20/50 oil (have run that before in the winter) instead of 10/40, since it won't harm anything, and might prevent the same from happening again.

But I'm talking about two different cars. The oil pressure light/alarm issue is with the 100CS and only happened twice with each occurance happening within 5 miles of each other. Since the car is running perfectly and the oil pressure is normal, I decided not to replace all the possible causes... senders, switches, sensor, etc.

Brake pad warning went off on the A6, three times in one day. Suspect that's a faulty connector or sensor, or whatever, so if it continues to happen in the future, I'll look into it.

So to get things straight...

'94 100CS, 92k miles, stock brakes half pad... oil pressure light/alarm went off twice. Car in Arizona.

'96 A6Q, 74k miles, new EBT brakes... brake pad warning light went off three times. Car in New York.

Brake parts inventory of mine:

Ferodo pads - Front
PBR MM pads - Rear
Stock rotors - Rear

If I keep the 100CS long enough to wear down the brakes (maybe 15k longer) then these and maybe a new set of slotted rotors will go on the 100CS. Was planning to replace the brakes this week, but they really don't need it and there are no problems with them as they are.

I'm not at home, and don't have a printed version of it with me.