I have a really sweet Volvo 7XX series turbo. Ever since I washed under the hood, the car intermittently runs really rough after the engine is hot. Today, just sitting in 95 degree sun for several hours, I drove it 5 miles home and I didn't think I'd make it up the road which has a slight grade to it! A mechanic I found came and got it, blew black smoke when he started it. He took it, changed spark plugs, drove fine for him, brought it home and I'm still having trouble with it. Did run better at first but now is just getting worse, especially after engine warms up.

Other problem I'm having is that the push button OD doesn't always result in the car shifting. Did clean under the button and that seemed to help a lot but button is still not as responsive as it should be.

Any ideas? especially on the running rough problem? Car has about 216,000 miles on it.

Thanks. Judy