My mom's Toyota Camry revs as high as 4500rpms in both park and neutral and stays that high until put in a different gear any ideas would be much appreciated
This sounds like a severe vacuum leak. You are going to be looking at either a bad intake manifold gasket, bad throttle body gasket, or cracked intake manifold. A brake booster hose MIGHT be able to move that much air.
A couple things to check first. Vacuum hoses, including the brake booster hose. Pull off the intake hose and look in the throttle body to see that it is closing all the way. Clean the EGR valve (if you have one) and verify it is closing.
To check for vacuum leaks, you can use something like carb and choke cleaner and spray the hoses that should be sealed. If your idle varies, then you have found the leak. Just be sure that the spray you use wont degrade the hoses and is ok to be consumed by the engine. I believe carb and choke cleaner will not eat the hoses, but double check before using.
I was going to suggest checking for codes, but an '89 likely doesn't have an OBDII port.
I don't know if a Camry that old has an idle air controller, but if it does, I'm wondering if it's stuck open. Only thing is I'm not sure the IAC can get that much air into the engine.
I hope that helps at least some. Nice to know they last that long, I have a 2000 Camry LE..