Vehicle: 2002 Ford Explorer, 2WD, V6-4.0L, VIN E, Automatic Transmission/Transaxle

Mileage: 171,119 miles

Problem: This Explorer arrived in the shop with diagnostic trouble code (DTC) P0202 stored in memory and a slight misfire on cylinder #2. The technician tested the injectors with a noid light and determined #2 fuel injector had failed. He replaced fuel injector #2, the intake gaskets, a PCV valve and the differential pressure feedback EGR (DPFE) sensor because it was broken.

Case Details: After the repairs, the engine was hard to start and set, DTC P1131 - Lack of HO2S-11 Switch - Sensor Indicates Lean for the B1S1 O2 Sensor.

The technician tested the fuel pressure. It was 65 psi with the KOER and did not drop below 60 psi after one hour with the engine off. He smoked the intake manifold and found one of the new manifold O-rings was leaking. He replaced the leaking O-ring, so there were no more vacuum leaks. With the KOER, the vacuum was 22 in hg with the needle holding steady. The technician replaced the O2 sensor with an OEM part but still had the same issue. The engine ran well off idle and had good power.

A Tech-Assist consultant suggested checking the EGR system components and operation. The technician removed the EGR to determine if it was stuck open and found that there was a rust hole in the wall of the chamber. The hole was allowing exhaust to flow even when the valve was closed.

Confirmed Repair: The technician replaced the EGR valve and cleared the DTC. After the repairs, the vehicle started easily and had no further issues. Problem solved!