Bad Mass Air Flow Sensor on 2002 GT?

tracyballard

New Member
Jul 4, 2011
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I have been working on a Service Engine Soon light for a while now on my 2002 GT. the first time it came on I had Autozone check the codes and I got 0171, 0174, 1130 & 1150. I changed the spark plugs, cleaned the MAF with MAF cleaner and the throttle body with TB cleaner, and also replaced a hose that had a 2 inch long crack in it - the short hose that comes off the PVC valve on the passenger valve cover.

After the work - the Service Engine Soon light went out for a few days after I did that, going maybe 20 miles with it staying off, and running much better with more power and revving much more easily. Now the light is back on and it feels very sluggish again, I checked to make sure none of my spark plugs had backed out, no problem there, and had Autozone run the codes again - now it's only the 0171 and 0174 codes showing up, which means it's running lean on both banks. So....does that mean the MAF is the problem??
 
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My vote is vacuum leak. Check the valve covers, oil dip stick, intake gaskets, in short anyplace that unmetered air can enter.

However, the list is actually very long of possible causes. Check the fuel pressure for starters.


>>P0171 and P0174
Air Measurement System
MAF sensor (contaminated, damaged, malfunctioning, etc.)

Fuel System
Fuel pressure regulator (leaking, malfunctioning, etc.).
Fuel filter plugged, dirty.
Fuel pump (weak, check valve leaking, etc.).
Leaking/contaminated fuel injectors.
Low fuel pressure or running out of fuel.
EVAP canister purge valve leaking (when canister is "clean").
Fuel supply line restricted.
Fuel rail pressure sensor (incorrect reading).

Air Induction System
Air leaks after the MAF.
Vacuum Leaks.
PCV system (leak, valve stuck open, etc.)
Improperly seated engine oil dipstick.

Exhaust System
Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets, etc.).

EGR System
EGR valve tube/gasket leak
EVR solenoid vacuum leak

Secondary Air Injection
Damaged/malfunctioning secondary air injection system (mechanically stuck valve).
 
Double check your PCV lines for leaks. You have a vacuum leak somewhere. If the engine pulls in air from anywhere that does not get measured by the maf the EEC will throw lean codes.