2000 Mazda 626 61K miles. It started misfiring yesterday, As soon as I put it in gear it starts misfiring, once I gain some speed it is OK. Today it stopped twice, once while I was stopped at a red light.

The check engine light was on, so I took it to Autozone to have it read. It returned a code of P0301. When the guy put it in the computer to find out what was wrong, it returned "Not Avail". Tried to call the Mazda dealership to find out what the code means but the service department is closed for the weekend. Anybody out there knows what is meant by code P0301??

As it turns out the code P0301 means "misfire cylinder 1". any ideas what might cause this?

In order of expense:

Plug
Plug lead
Rotor arm
Distributor cap
Injector
Cyl head gasket
Burnt valve

Thanks Peter. So what is the range of expense I'm looking at here?

Start with the simplest and least expensive repair. You can run a compression check to eliminate bad valves or bad head gasket possibility. Then take out the plugs and check for signs of cracking in the porcelain insulator. This will cause a serious miss. Take plug wires and do a resistance check on them (rule of thumb: 1000 ohms per inch of length).

When was the last time you changed the plug wires? These cars require new plug wires every 60K miles to be reliable. Chances are, you may have this problem. I would also inspect the distributor cap.