whittles

I am having a problem with a hesitation on the car and it comes up with code 22 which is actually 1259 Vtec in the book. The meter says it is a air/fuel metering problem. The shop I took the car to said that I should first change the fuel filter, which I started to do. It's a pain and I could not get the compression fitting off on the botom side. Does anyone know a trick to this? Or am I wasting my time doing this?