Could use some help. I have a 2004 Saab 9-5 with 202k. It has had an oil leak for some time now that I think is related to the oil pressure switch. I drove it my parents about 2.5 hrs away combination of highway and city with some step hills, but it seemed to run ok. Yesterday I checked the oil level and the dip stick wasn't registering at all. I put about 1.5 quarts of oil in it and drove it a little bit without issue. My son then drove it back home the 2.5 hrs and half way into the trip called saying it was really shaking when idling. I got home this morning and started the car. First time it didn't start and there seemed to be a high whine in turning it over. The second time it started up but there definitely is a violent shake in it. I checked the oil and it is good. I'm afraid even to pull it out of the garage as to it dying on the road. Any ideas would be much appreciated. Thanks.