Two taps are pouring okay. One tap is all foam. Why?
They are all part of the same kegorator. Three taps from three kegs in a converted freezer.
Well . . .
Do they all have the same hose length?
Are the all on the same pressure? Are you 100% sure, meaning you didn’t over carbonate it by force carbonating at 30 psi and are now pushing at the same pressure as the other two?
Assuming the answers are yes, there is probably some restriction in the line causing the problem. Look at the line itself, is the beer foamy right out of the keg? If so, check the poppet. Does it start to foam on the way to the faucet, or only when it’s coming out? Debris in the faucet or the line can cause foaming, as can a kink in the line.
could be an air leak too. if your lines aren’t clamped down properly.
I had a post earlier (that I need to update with info) about the same issue. I opened up the kegerator and started pouring to see where in the line the problem was coming from. Straight from the connector, by all appearances, just like beerocd says. Gonna try to cut it and re-clamp this evening to see if it works.
Yes, great point, could be an air leak. 
it foams right from the start of the keg, but pours okay when I attached the other lines to it.
I discovered alot of irregularities in the hole in the shank. There are bits of metal sticking up in the shank hole. Would that make the whole line foam from the keg?
It shouldn’t. If it doesn’t foam with the other lines, then it’s clearly something with that one. It’s possible the liquid out coupler is dirty or isn’t fully pressing in the poppet for some reason or is leaking air into it. I would take it apart and clean it, then try again. There’s a slot on top that you can put a screwdriver in and the whole thing comes apart, just make sure you pay attention so you can put it all back together. :)