Hello Everyone,

I have a 2000 volvo s80 with approximately 140K miles on it. I am having acceleration and/or engine problems, I just replaced my battery and when I went to drive, the car would not accelerate properly. What I mean by this is that, it accelerates slowly but when I try to accelerate real quickly by flooring the pedal, the engine will not exceed 4500 rpm and I have to wait for the rpms to drop back down to idle before I can then SLOWLY accelerate. When the engine hesitates there is no acceleration until I wait for the rpms to drop back to idle. I thought it may be a transmission problem but I put the car in park and when I hit the gas, it does the same thing, the engine hesitates and sometimes even goes from 1500 to 3000, drops and does that repeatedly. I had the car hooked up and the codes came out as P136 and P156 which relate to the oxygen sensors I believe. This problem only started to occur after I replaced the battery...? Has anyone had this problem? Any help or suggestions will be greatly appreciated!