Hi,
I recently had my engine "tweaked" in order to get it to pass the smog test here in California and am now having some problems. The mechanic adjusted the engine so it would run leaner. I passed the test but two days later the car starts running very poorly. It's almost impossible to start, it idles very rough and often stalls at intersections or when going around corners. I don't think it's safe to drive.
When I took it back to the mechanic he claimed that the engine compartment wiring harness was shot and that that was the cause of all my problems. He also said this is common. I don't know much about Volvos but that doesn't make sense to me. When he told me that he wanted a $1000 to fix everything I really became suspicious. He seamed surprised when I told him not to replace it. Does it make sense that the engine compartment wiring harness could cause these problems?
How hard is it to replace a wiring harness? I've never done this before and will need to work in the street.?.
Help.

Sott
86 240 Wagon 150,000 miles