Hello Christopher,
I am not a mechanic either, however, that does not mean we can not read and educate ourselves on the issue at hand. What I am trying to say is that this web side is fully dedicated to people like your and I to help one another. Members that started this site have set up a "Technical Manual" and "Special Notes" This however, is only accessable to "Full Members" The yearly fee is very minimal and I like to refer to it as "worth it's weight (amount) in gold" I say this since you can access a wealth of information that for excample members here have compiled and organized from precisely issues like yours.
My point is, once you are a full member here you can read all about it and then you can talk to your mechanic (or even check things out yourself) in the end you save a fist full of money form things you read and learn on this web site. One thing we have in our favour here is that due to the age of our cars a wealth of information has been gathered and exchanged among members here. You will find this in only a few web sites.
From your problem description I think you have an issue with your throttle linkage (let's hope it is not a transmission issue). Obviously it was okay before and something changed suddenly. I can only summarize that for whatever reason something in your linkage adjustment has changed that caused your RPM issue. With todays high hourly rates that the shops charge for our cars you will be able to check some of the points yourself and as I said earlier "save a fist full of money"
Good luck and welcome to the forum!
