Boxster running rough no

[mikesz]

Had CEL. Last weekend I got under the hood and changed the air filter it was the worst I have ever seen. Got the shop vac and vacuumed the airbox before replacing Filter. took out the MAF and cleaned it but it didn't seem to be dirty. Disconnected the battery for 40 seconds to reset the CEL reconnected and Drove around for 100 miles and no CEL. Took the car to be inspected and passed. Last night I was on the highway and hit the throttle and the care was running fine then it started running rough and backfiring through the drivers side air intake. I limped to my friends house waited about 30 minutes then started it up and car ran fine but I had CEL. Got it home ok. Went out with the durametric and checked codes 1128 and 1130. I cleared the codes with the durametric software. started the car up and went for a short ride and started "popping" again and no power. Parked it in the driveway for now. Any ideas what causes this? Up until this happened car ran great. But I have only had it for a couple of months. Seems like for every one thing I fix another thing goes.