Title says it all. The 97 GT I just bought a while back recently threw a rich code when driving, then developed a pulsing/surging in 5th gear at the same time. No matter if I clear the code, the pulsing/surging in 5th is always there, and idle randomly gets really rough. Code is P0175.

Here's the real problem though, I had just replaced another 02 sensor that was spiking as well, but this sensor was spiking within what you'd consider possible for a 14 volt system (lower than/around 14 volts).

The shop said the sensors looked OEM, so I'm going to replace all the others and run it for a couple weeks while constantly clearing codes.

Any thoughts or previous experiences would be awesome!

Thanks,
Blake