-GOT THIS TRUCK ON MONDAY ,DTCs P0171 AND P0174 AND P0300 .
VEHICLE STARTED AND RAN NORMALLY WHEN FIRST TIME START IN MORNING .BUT AFTER COOLANT TEMP OVER 70 C ,BOTH BANKS WILL RUN
LEAN CONDITION .STFT AND LTFT WILL INCREASE AND REACH 32% AT IDLE .HOLD RPM AT 1500 ,STFT STILL STAY AT 32% ,BUT LTFT WILL DECREASE TO 0% ,HOLD RPM AT 2500 ,STFT WILL STAY IN + - 10% ,AND LTFT STAY AT 0% .
-ROAD TEST VEHICLE ,IDLE ROUGH AND LACK POWER ,ENGINE RAMDON MISFIRE IN ALL CYLINDERS .VEHICLE SILL STALL WHEN STOPPED AT STOP SIGN OR TURNING .
-HIGH WAY SPEED ,NO MISFIRE, DTCs P0171 AND P0174 NEVER SET BACK .STFT AND LTFT ARE IN THE SPEC ,TOTAL FUEL TRIM ADAP NEVER
OVER 10 % .
-PERFORMED VACUUM LEAKS TEST ,USING WATER SPARY ,PROPANE AND SMOKING MACHINE ,NO LEAKS FOUND .SWAPPED PCV AND BLOCKED EGR VALVE ,NO CHANGE .
-CUSTOMER SAID THIS TRUCK WAS REPLACED FUEL PUMP BY BACKYARD TECH .SO CHECKED FUEL PRESSURE AND VOLUMN ,57-59 PSI ,PASSED .1.2 L GAS VOLUMN IN 20 SECONDS ,PASSED TEST TOO .
-DRAINED FUEL TANK AND FILLED WITH NEW GAS ,NO CHANGE .
-ALL SPARK PLUGS WAS REPLACED WITH OEM ONES BY OTHER TECH .
-EXHAUST LEAK TEST ,NO LEAKS FOUND .
-SWAPPED MAP SENSOR AND BOTH UPPER STREAM O2 SENSORS ,NO CHANGE .
-THE NEXT STEP ,I AM GOING TO CHECK ENGINE COMPRESSION AND PUSH RODS .DOES CAMSHAFT
DID I MISS ANYTHING ?