The car has 124000 miles and idles very roughly after warming up. We have replaced plugs and wires, all filters, PCV valve O2 sensor. any ideas on why it is still running poorly.
Perhaps the throttle body needs cleaning (use throttle body cleaner).
Maybe even a faulty IAC valve.
MAF sensor working? Any vacuum leaks?
I had similar problem years ago with a Dodge…it was the EGR valve.
i was driving my 96 corsica home one night and i stopped at a gas station and noticed it was running rough i did what you did wires pluges all that and found that one of the coil packs were bad took them all in to autozone for testing and one was bad i would try that let me know what happens