[93stangfutr5.0]

ok today i check my ecu and i gave me an error code 538 this code has some thing to do with rpms changing to much when checking the engine just wondering how to fix this.

[b_chandler]

I'm assuming this is the KOER test?

538 means it didn't receive the "goose" in the middle of the test. There's a part of the KOER procedure where you have to blip the throttle. Failure to do so throws the code.

[93stangfutr5.0]

thanks but ill try it again one other question though could the timing belt also cause this it says it is off by 10 degrees.