P1151 and P0133 Fault Codes in 1999 Ford Explorer 4.0L OHV - Causes and Diagnosis
I own a 1999 Ford Explorer with a 4.0L OHV engine and automatic transmission. After extensive research, I've found that the combination of fault codes P1151 and P0136 is relatively rare. I'm wondering if both oxygen sensors could be failing simultaneously, or if there's another underlying issue I should investigate. I've already performed a vacuum leak check with no positive results. The vehicle recently underwent a tune-up by the previous owner. Could this have affected sensor performance? Any guidance on how to properly diagnose these codes would be greatly appreciated.
It's important to verify whether the previous owner installed aftermarket oxygen sensors during the recent tune-up. If so, those non-original sensors may not function correctly and could trigger P1151 and P0133 codes. Replacing them with OEM factory-installed oxygen sensors from an authorized dealer is recommended for accurate readings and reliable diagnostics.