Hi, Im having trouble diagnosing a misfire on my 97 trans am, I dont have any modifications other than long tube headers which dont have the post cat o2 sensors which I never got tuned out so I have those codes. As for the misfire whenever I try to accelerate at around 50 mph the car will start to misfire with no acceleration and eventually will get going again and stop having problems. The car runs rich with the LTFT being around -15% sometimes getting around -20% short term being similar as well. Spark advance is also typically around 20+ degrees getting as high as 40 or so during acceleration, (I dont know if thats an issue in itself or not), while the car misfires the advance drops to near zero with the fuel trims also dropping closer to zero. Other codes that are being thrown are slow response for O2 sensers, Evap (or EGR i cant remember), bank 1 and bank 2 running rich. Unfortunately thats about all the information I have, any hints would be great and Ill try to get any information yall need. (sorry for the poorly written post)