I just got my car and when i start it , it revs to 2000rpm
after 1 minute its up to 3500rpm and doesnt seem to fall. Does anyone know whats wrong? vacuum leak?
i checked the throtle cable and its fine
not sticking or anything

 

anyone?

 

my 88 used to do that , but if i'd tap the gas it idled back to normal. sorry this isn't a very technical answer

 

It's probably staying on fast idle cam. Check to see if the linkage is off the fast idle cam after warm up eg thermowax disengages fast isle cam when warm, and make certain throttle cable not too tight.
If you need info on the thermowax give a search. A zillion posts.