I have a 98 cobra. It threw a p1143 a few weeks ago which is an evap system concern. And it began hesitating under light throttle probably 1/8 to 1/4 open. It's kinda like a misfire or detonation. After I cleared that code a p1151 popped up and has since been the case. I believe this is an o2 bank 1 code. But I don't know if it's upstream or down. I have an o/r x pipe with MIL eliminators. Anyone else have or had an issue like this?