SES Light is on. PO300,PO171,PO174

[Lo01qx4]

This light has been on for about 10,000 miles. i have a '01 infiniti QX4 4x4. at first i didnt notice anything unusal but now the problem is real bad. the light does go off by itself sometimes ,then comes right back on again. the main thing is that i lose power when driving and sometimes likes stall out when i'm stopped. the mechanic says that it could be a vaccum line leak or intake gasket leak. he check for it but did not find the leak and says it could be the intake gasket. have u heard of this problem with this vechicle if so what do u recommend i do. i dont want to take it to the dealer cuzz i'm afraid it gonna be real expensive but if i have no choice then i will.

[nissandoms47]

P0171 and P0174 are fuel related problems. The engine is running lean. which could be an intake leak and is most likely. Check from the airbox to the throttle body. im sure something is cracked or broken.

This is copied from the FSM

Intake air leaks Heated oxygen sensor 1 Injectors Exhaust gas leaks Incorrect fuel pressure Lack of fuel Mass air flow sensor

any of those could cause those 2 codes.

P0300 is multiple cylinder misfire, which is probably caused by the leaning.

fix the first 2 and i bet the last one will go away. after resetting the ecu of course.