Yo got a 97 dak . 3.9 magnum. Check engines been on and off . Code is p0132. Upstream O2 sensor . Rich gas smell in the exhaust .hills are a bitch. Got no ***** after 75 mph . Not sure if it's plugs . The sensor . Or maybe the cat . Any clues guys

 

How's the plenum? Clogged cat is always a possibility if the plenum is blown. Moving to the correct section.

 

the up stream o2 is what adjusts fuel and air, that would effect performance. as for the cat if it was plugged, you would have problems with the down stream o2 it checks if your cat is working.

 

Replace the upstream would be a starting point. If you can smell fuel, it's stupid rich. Could have a stuck injector as well.