[hharney]

I would suggest you find a reputable shop that is familiar with pressurized aircraft and save yourself a lot of grief. The pressurization system is pretty much the same on most Cessna's so there should be a shop in the area around you that can take care of your problem. It could be the valves are not closing completely or a door alignment issue. You might pay a little more in the beginning but at least you have a shop behind the work. Get some references and find some knowledgeable folks out there.