Studnike13

Hey guys, need help here. I was driving down the freeway the other day, at about 75 mph, and all of a sudden it seemed like my engine shut off. I hit the gas and got nothing, so I down shifting and hit the gas and the car lagged, didn't really take off as it normally does. Did that a couple of times and it finally responed, as I exited the freeway it did the same thing. And as I came to a stop, it started to idle rough, and 1st gear did get too much response. I checked the codes, and P0171 and P0174 came up. I looked it up, and it reads, P0171 - System Too Lean (Bank 1). So I cleaned my MAF sensor, and put in a new fuel filter. Its still doing it though. I'm thinking of taking into the dealer and have them trouble shoot it, and I will go from there. Any help would be appreciated. And I also put some Techron in my tank, in case it was that. Thanks guys.

charliebrown266

p0171 is bank one lean and p0174 is bank two lean! the number one cause of these codes are vacuum leaks!

SpartaPerformance

Possible causes:
• Fuel system:
* Damaged or leaking fuel pulse damper
* Fuel filter plugged or dirty
* Damaged or worn fuel pump
* Leaking fuel pump check valve
* Leaking/contaminated fuel injectors
* Low fuel pressure or running out of fuel
* EVAP canister purge valve is leaking when canister is clean
* Fuel supply line is restricted
* Fuel rail pressure sensor bias
If you have a 05-06 there is a TSB on fuel pumps.

• Air induction system:
* Air leaks after MAF sensor
* Vacuum leaks
* PCV system leaking or valve stuck open
* Improperly seated oil dip stick
* Damaged MAF sensor
• Exhaust system
* Leak in manifold gasket or mating surface before or near HO2 or EGR
* Vacuum hose disconnected on EGR system module applications
* EGR valve/tube gasket leak
* EVR solenoid vacuum leak
* Damaged secondary air injection system or Mechanically stuck valve

Some of these causes may not apply to specific applications