Bought this car 2 months ago and this has happened twice now: I'll be driving along and notice that the car seems not to be able to decide which gear to be in, especially when accelerating/decelerating, and jumps around between gears. Then, the next morning I go to start it and it runs really rough, the check engine light comes on and the codes are misfires on all the cylinders. By the way, does anyone know what code 1310 is? The guy at Autozone couldn't identify it, and my volvo guy says it's not a volvo code. Anyhow, the car will run smoother as the day goes on, then the next day it will be rough again, but not as rough, and by the end of the day it's idling smoothly. The next day, the problem is gone and it idles as good as new for a few weeks. My indy Volvo guy (Robert's Volvolab in No. Reading MA) says it's too hard to tell what it might be if the car's running well when I bring it in. Any ideas what this might be?

Also, Robert up at the Lab suggests using mid-grade gas from Texaco or Shell only, and says Mobil sucks. Thoughts about that?