car idle surges high then lower then normal. dies out too

scan for codes, clean idle air control valve, check for vacuum leaks.

Hello, those procedures were all performed and still the same issues. I should also note the air idle control valve was changed and it ran good for 3 days then the same problem. bad control valve? Wiring issues? Also there are no vacuum leaks. No codes either. Any other suggestions would be appreciated. T Y

Hate to say it, but the new iac could be bad. There are several good videos on youtube on how to test it. I would do this for sure. Also, if it is bad I would suggest also that you always use OEM electrical parts when replacing them. I have had much trouble with aftermarket crap that its just usually not worth it. Also, check all the fuses and relays.

Hello, the AIC valve was tested for voltage and it was fine. Would worn spark plugs cause this? I had a mechanic pull 2 random plugs and he said they were pretty well worn. This was not checked at first because the car ran fine. Any chance this could remedy the situation? T Y

Yes, an overdue tuneup can cause all kinds of problems.

Hello, a complete tuneup was done. Same issues. Any other suggestions?

Ok, you might need professional equipment to find out. You can get a fuel pressure tester and do that yourself, but I would suggest having a mechanic with an engine analyzer hook up and retrieve live data while the vehicle is running. It will give all the info needed including fuel trim.