MARKSSTANG

I recently put in a forged long block from MMR, with a compression ratio of almost 12:1. I got a XCal tuner to help adjust with the timing, and I still have to run octane boosters on top of 91 to keep it from knocking. Now, I am getting a check engine code P0452 which is "evaporation system fuel tank pressure sensor circuit - low output." My car is also acting funny while driving. It's an automatic and while driving at a constant speed (around 40 is most noticeable)and a constant throttle position, the car bucks back and forth like it can't figure out whether it should shift or not. Is there something wrong with my tune? Is my engine misfiring? I've replaced my gascap, the fuel pump, and the sensor circuit to try to fix that code, and it still comes back. Any advice would be greatly appreciated!!!

Mark

onegreedy

bad tune!

that code shoudlnt give you any driving issues