My catalytic has gone bad. On top of that, the mechanics claim that because I did not have a gas cap, there is a lot of gunk inside the tubings and therefore my car is not passing smog. Is there a way to still register the car without passing smog in CA as the costs for repair are about $1500 and the car is worth $1400.

There are some options... you can register it in a location that doesn't require smog registrations. Got a friend with a house out in the sticks?

There is the whole 'referee' program, where you can get a break after you've spent a certain amount of money.

I don't believe the part about the gas cap and gunk - Find another mechanic, or do it yourself - a new fuel filter is $20, and a can of 'seafoam' is $6 - that will take care of the fuel system. A new catalytic converter shouldn't be more than $400, and could be cheaper - installation better not be over $100.

Keep trying. I've found that different smog places are different with respect to the inspections. The 'Test Only' places are run by people who have bad attitudes. Ask around for a good one in your area.

just a buy a new gas cap and catalytic converter. a gas cap, 5-10 bucks, a cat, 70-150 bucks, and use a fuel system cleaner, 7-10 bucks. for some good deals on cats, go to ebay. the installataion isn't all that hard unless u don't know crap about cars.