Originally Posted by Bonneville94V688
Change the o2. I bet that'* a contributer to the bad MPG'*.
dont use a bosch either, get a OEM from the dealer or pay half the dealer price at GMPD.
I'd also do a full tuneup, plugs wires, air filter.....
Not sure if you are close to anyone with a OBDII scan tool, you may have another sensor making it run too lean or too rich. I'd replace the plugs, wires, and o2 first before anything else though. this has always gained me a couple MPG with every car I've owned