Hey,I have a '99 Honda Accord (4 cylinder VTEC) and I had a new gas tank fill-up last week. Ever since then, my car has started to hesistate when I try to accelerate, although it does this only occasionally. Moreover, sometimes my car's idle is rough, like the rpm nominally stays around 800 and it suddenly falls to 300 or so and recovers to 800 in 1 or 2 seconds. A few days after all this, the check engine light came on with P0420 code (and its the only code). Although the code says that the catalytic converter efficiency is below threshold and something maybe wrong with it, I am not sure if a bad catalytic converter can cause my car to sometimes hesitate and exhibit rough idling.Could P0420 appear if the gasoline I filled-up with was of poor quality?I would really appreciate every advice from you.Thank you!

 

yeah it can come on due to bad fuel

 

Sounds to me like your cat may be olugged. THe flow restriction would give yuo a P0420 and hesitation.