Nothing is more frustrating than down shifting to 5th in an effort to pass someone on a two lane road and having an O2 problem that disables you from passing. UGH! My 2003 GLI is running really weird. I can tell it's the fuel/ratio so I had the codes checked and it came up with P00118, P00300 and P00304. All basically a fuel/air ratio problem or cylinder misfire. I bought a new ECT sensor to fix the P00118 problem and bought some Mass Air Flow sensor cleaner. I'm going to get under the hood tomorrow and try to replace the ECT sensor and clean the other sensors. Any suggestions or has anyone had a similiar problem? I'd like to DIY it, but need some guidance and being a female you can't really get good guidance from the average mechanic. I can redo my plane's engine, but can't figure out my GLI. Thanks in advance!