two questions

[fastest stock 87 gt]

first ran codes tonite and got code 91 now is this the passenger side ego. sensor 2nd would this code cause a rich condition on that side.
also temp gauge quit working could that be from ect not working even though no code came up

 

[fastest stock 87 gt]

help anybody

 

[Mavrick]

Thats the passenger side oxygen sensor, so ya it could mean a lean or rich condition.

 

[HISSIN50]

and the temp gauge runs off of its own sender. it is a one wire sender behind the dizzy. the ECT is totally different and on the pass side. they have nothing to do with one another.

might try doing a balance test on the injectors to see if one is not working, and causing the code.
good luck.