I have a 1998 Neon, the car starts and idles fine, when I drive it, it will stumble and surge sometimes while taking off from a light or stop sign. I have a check engine light on, and I get codes po505 and po122 when scanned, I have cleared the codes through the scan tool, drive the car the light comes back on and the codes reset, I have cleaned and inspected th IAC, but no fix. Any help would be great, thanks.

 

have you tried replacing the IAC or the TPS?

Also, I know those are the codes you are getting, but have you checked the spark plugs?