Nissan Repair: troubleshooting/maintenance of nissan pathfinder SE, mass airflow sensor, volt ohm meter

Question
hi, i really appreciate what u do. please keep it up.
Recently , bought a pathfinder se 2001 model,after about 4 months the following begin to happen.

squeaking sound anytime i press  the brake pedal
the engine jerks,kinda like convulsing when im accelerating.
noticed that i cant rev the engine more than 2-2.5 (000)r/min without it jerking
noticed unfamiliar engine sound on idling and at that moment ,the rev/min gauge jumps up slightly.

pls, what does all this truly indicate?

david

Answer
David,

First, replace the brake pads with factory ones.  courtesynissan.com for parts is a cheap alternative from the dealer.  Also, buy a brake shim kit to eliminate the noise.  I would check for codes on the jerking.  I would think the mass airflow sensor is shorting internally.  This needs to be verified with a volt ohm meter since this usually does not throw a code.  Also, another item that will cause the condition is dirty fuel injectors.  Have the fuel pressure checked for normal pressure and for a really fast leakdown after the engine is shut off.  If the system does not hold pressure for several seconds it means you have leaky injectors.  An ohms verification should also be performed.  If you are doing any of the aforementioned yourself get a Haynes Manual or a factory service manual.  You can purchase the factory one at nissantechinfo.com by setting up an account and providing your credit card.  I think it is still $20 bucks for an hour of access.  The manual is in PDF format.