Hello, so I have changed spark plugs, wires, timing belt, water pump, k&n intake, vapor canister and more, but I still can't find out why my xd is driving so damn slow, I was thinking maybe a bad 02 sensor, so i went and checked it out and I found out I have the 132hp sulev engine not the 138hp ulev engine like my last xd. What would I need to do to convert to ulev? I have no check engine light but the car seems to be running rich. When the timing belt was changed I noticed a big difference but the car still doesn't even compare to my last xd's performance. Not to mention I'm probably only getting around 15-20mpg city, my trip computer says 23-24mpg but we know that isn't accurate. The car is at 190k miles so obviously that is a factor too.