'91 TDI valve problem
 

I am looking at buying a 1991 Jetta TDI. Only problem is that 3 valves don't come back up according to the mechanic he took it to. Would this be a big problem, or an easy/cheap fix?

I am mechanically inclined and can do this myself, but i'd like to know from some of you guys what this could be. And where is the best place to get parts for these cars?

Thanks

Oh and also, i've seen a couple for sale with the tranny stuck in 3rd gear. Is this a common problem? and is it easy to fix?

Thanks