So latest update- I replaced the air filter and installed a new MAF. I have run almost a full tank with the BG44K system cleaner. Unfortunately, it is still slow! Just plan lethargic and no fun. However, not horrible either. Just feels like I need a lot of pedal to make it go. I have been pretty much flooring it everywhere I go hoping to clean it out or something. While driving like crazy I did get a CEL P0420. I reset the light and just today got another CEL this time P0171 (ECU trimming fuel excessively) and P0420 (catalyst system below threshold). I am starting to think I may have a catalytic converter issue. I spoke with the PO and he mentioned a while back he had rough running engine issues. He took it in and had the coils and spark plugs changed. This he said resolved the problem. Also, he told me he has been driving the car for the last 5 years 100 miles per day commute to work. He said he did not notice it being slow because he only drove highway and babied it for gas mileage. With all that said, any thoughts on what to check next? Should I just take it to the stealership and have them diagnose?