Can anyone tell me how i can tell if my aem wideband is going bad or some sensor on the engine. The aem use to stay close to 14.2 14.7 at cruise speeds now its either dead lean or 12-13 rich . can o2' sensors be bad without a ses light on? also i still think the engine has a very rough idle. idles around 14.7 steady. I have no way to scan, I thought if it was going that lean at cruise it would throw a code?