Could a bad O2 sensor make the engine run lean?
I'm pretty sure it's bad. I have no codes, but the engine has NO power. When I mean no power, I mean that my buddies 2.4 TJ is quicker then mine. Often times it gets warm (about 215-220) going up hills. My radiator looks cleaner then a hospital, and it's full of coolant with no leaks. The water pump only has 20k on it, so I know it's good. After thinking about it, i think the engines getting warm because it's running lean. Also causing it to have no power. I was thinking the cat, so i put a vacuum guage on it. Everything checks out good with vacuum. With a bad cat, when you blip the throttle, the vacuum will change slowly. However, with mine, it's very quick. Plus, it doesn't rattle. I had a thread earlier asking about the gutlessness, so i just wanted to ask if thats the problem. If its something else, i'd rather save the 60 bucks
1990 YJ-The wheeler
2015 JK- The DD