My buddy has a 1995 mustang gt, its boosted(turbo) and been tuned. He said this was a problem before the turbo. He took it to a shop and they could not figure it out. There is 300mV coming from the O2 sensors no matter what. The computer will show 300mV from the O2 sensors even if you disconnect them. He said it is causing it to run rich. They have swapped the computer and still the same 300mV. Any idea of the problem?????