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?????

 

Bad wiring harness.

 

any other ideas?

 

Troubleshoot the wiring harness.

 

why would you even bother to ask if anyone else had any ideas.. the problem is OBVIOUSLY a wiring issue..

get your hands on a wiring diagram. cut the appropriate wire at the ECM, and run a new wire to the sensor... done!