1987 Cavalier stalling

I have a 1987 Cavalier that wants to stall when I am stopped. It also seems to want to run to high at highway speeds, like it doesn't want to slow down even when I take my foot off of the accelerator. I have replaced the spark plugs and spark plug wires. Any ideas on what is causing this problem? Thanks in advance for any help.

I had an 89 Z24 that had similar problems and it turned out to be a sticking EGR valve

I had an 89 Z24 that had similar problems and it turned out to be a sticking EGR valve

Matts3100, thank you very much for your advice. It turned out to be the EGR valve like you said. I replaced it and everything is fine now. Thank you again!