Mass air flow
If the car runs better with the MAF unplugged then I would suggest you clean off the MAF with isopropyl alcohol and/or change out your o2's if they are old. I recently had surging and hesitation under load when driving and the car kept throwing codes for the MAF circuit and o2 circuit. I unplugged the MAF and the surging and hesitation went away. However the car was running very rich as someone else mentioned. My gas mileage took a noticeable dip. Then I installed a known good MAF that I borrowed from a friend on the site. The car started to throw o2 sensor circuit codes. I replaced all the o2 sensors with new denso sensors from Rock Auto (very affordable) and I thoroughly and very gently cleaned the MAF with alcohol and a q-tip and now I have no codes and the car runs as it should.
