I have a goodman model gmp 125-4. Last night I had a limit switch open code, I fixed it, the fan limit switch. Tonight I get a code 5 "false flame sensed", "gas valve stuck". I hit the valve with a scredriver handle, because I was told it might losen up the gunk sticking the valve. When I hit the valve, I heard a small amount of gas flowing through the valve. So, I know it is definitely a bad valve. My question is, Is there any way to clean the valve so that I don't have to buy a new one? I'm to broke to buy a new $100 dollar part, or call a service man. Please help!

Look it over. If it has a screwed on cover, take it apart and look at it. Note, it has a spring in it that could throw parts everywhere. Clean stuff up. A trick for reusing gaskets that have taken a set is to steam it over a pan on the kitchen stove good. Unless it is so old, it has hardened, it should flatten out and form a good seal like a new gasket. If it has an adjustment screw, not only leave it alone, it could mean replacing the whole valve is not a DIY project.

It is in violation to Federal and most state laws to open, repair or alter a gas valve, other than allowed by the manufaturer, which basically means you can change it to LP or NG.