Okay I did some digging but didnt find anything of use. I recently got a 99 gt with 91k miles on it. All original except for a few things, in excellent condition. Im confused on a few things. I reset some codes the other day and theyre back. Theyre P0171 and P0174. They state that both banks are running lean. I also have a code for P0442, something about an evaporative emissions control leak. Could this one be related to the other two? Also, if it helps... the car has a brand new intake manifold, new cold air intake, new plugs, and new accel coil on plugs. i noticed a hose was pinched under the coil pack mounting bracket where it meets the throttle body. I believe it was the pcv hose? Its an elbow directly under the iacv. I replaced the hose with a new one and re routed it so it wouldnt pinch. I had a stumbling idle and occasional die after a warm start here and there. I dont know if it still exists or not because i havent drove the car since the new hose. But anyway, is any of this in relation to each other? Any help is appreciated. Thanks!
Throwing Obd Codes?
- Thread starter Salty_Cobra
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Was there a vacuum leak associated with the replaced hose? If so, suggest that you reset the codes and drive it. P0171/P0174 are often associated with vacuum leaks.
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P0171 - System to Lean (Bank 1)
P0174 - System to Lean (Bank 2)
Air Measurement System
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P0171 - System to Lean (Bank 1)
P0174 - System to Lean (Bank 2)
Air Measurement System
- MAF sensor (contaminated, damaged, malfunctioning, etc.)
- 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 leaks after the MAF.
- Vacuum Leaks.
- PCV system (leak, valve stuck open, etc.)
- Improperly seated engine oil dipstick.
- Exhaust leaks before or near the HO2Ss (exhaust manifold gasket, mating gaskets, etc.).
- EGR valve tube/gasket leak
- EVR solenoid vacuum leak
- Damaged/malfunctioning secondary air injection system (mechanically stuck valve).
Well, there wasnt actually a vacuum "leak" it was a pinched off hose. However, i reset the codes and drove it a good 40 miles today and the check engine light never came back up. Not to mention it revs normal again and doesnt die. So im guessing the hose was the culprit.
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