Engine Mechanical problem
1998 Ford F150 V8 Four Wheel Drive 160k miles
My 1998 ford f150 started running really rough today and the check engine light started flashing. I took it to have the error codes read was told that the following error codes registerd on the computer: p0307 cylinder misfire detected cylinder number 7, p0401 Egr system fault, and p1151 accelerator position sensor aps property malfunction. The worker at Autozone said it was either the Mass airflow sensor, the Egr valve, Bad spark pugs or Bad wires. From you experience what should I replace first and what is most likely causing the truck to run rough?L
PO307 is cylinder misfire #7. This could be generated by the other fault
PO401 is EGR flow insufficient
P1151 is Lack of HO2S-21 Switch, Sensor Indicates Lean
check for vacuum leaks. Check/clean MAF sensor. Check items listed below
70) DTC P0401
This DTC indicates self-test has detected insufficient EGR flow. Possible causes are: EGR valve stuck closed.
EGR valve diaphragm leak.
EGR flow plugged or restricted.
Faulty EGR hose.
EVR VPWR circuit open.
EVR VPWR circuit to PCM open or shorted to PWR.
DPFEGR sensor VPWR circuit open.
Faulty DPFEGR sensor hoses.
Faulty DPFEGR sensor.
Faulty EGR VR solenoid.
40) DTC P1130, P1150, P1131, P1151, P1132 Or P1152: HO2S Not Switching
DTCs P1131 and P1151 indicate air/fuel ratio is correcting rich for an overly lean condition. DTCs P1132 and P1152 indicate air/fuel ratio is correcting lean for an overly rich condition. DTCs P1130 and P1150 indicate fuel system has reached maximum compensation and HO2S is not switching at the adaptive limits. Possible causes are: Fuel system malfunction.
EGR system malfunction.
Air intake or vacuum system leak.
Engine oil level too high.
Incorrect cam timing.
Restricted air cleaner.
Faulty PCV system.