I have owned this 2000 Volvo V70 AWD station wagon for only 2 weeks. 120k miles. The check engine light came on so I took it to Oreilly's and they hooked up the diagnostic tester. At first it gave no code at all. So the guy started the engine and then turned it off and it gave a code saying the catalytic converter could be plugged. The car then immediately would not start. It finally did and was running very rough. Before diagnostic testing it the car was running great. I was able to drive the car home about 15 miles and the next morning it started and still was running very rough. Almost like it wasn't hitting on all cylinders. Is it possible that the diagnostics tester messed up something in the computer? Strange how it started doing this immediately after he tested it. Or does this sound like a plugged catalytic converter and the timing of him testing it was exactly dead on? I am already regretting buying this car.