'02 with 110k miles. Not aware of any mods other than an aftermarket alarm. The CEL is on as well as the rev limiter. Advanced Auto pulled the codes P1607, 15-1, 61-1, and 81-1 (the last three indicated problems with a wheel speed sensor and some abs sensors). Tried to reset and the light and rev limiter stayed on. Took the gas cap off and made sure it was on correctly. The light stayed on, but rev limiter was gone. The next time it was started (two days later) the rev limiter was back and multiple attempts to adjust the gas cap had no impact.

Car was purchased in 2014 and driven at least weekly for about 6 months. After that it was driven or started at least monthly until about a year ago when the CEL came. Don't know whether the light came on at startup or while running. Don't know whether the Rev limiter was on when the CEL first came on or came later. Pretty sure the rev limiter is the reason sat for a year though. There also seems to be an issue with the EPS. Feels like the power steering goes out intermittently while driving and the wheels turn hard left on occasion when the car is started.

Any idea why the gas cap would affect the rev limiter or was that a bizarre coincidence? Is there any connection between the CEL and the EPS issue? Is there anything else I can try before replacing the ECU? Is a used ECU as big of a gamble as it feels like?