I have driving the car in the last two days and i noticed that once i have been driving for a while, and it has started jerking/pulling after a while driving. Once it turned off the car when i was getting ready to park, but it allowed me to turn on right away.

a mechanic checked the battery to see if it was the alternator, but said the voltage was fine and was also ok when the car turned on. does that sound like the proper way to check the alternator. i noticed that others say that they have a break and battery light go on.. is that a light that stays on when ur driving. like two days ago when the problem started when i turned on the car i heard a wierd noise as it started but went away. (heard other have something similar to that )

he tested the the fuel pressure and said it was fine (thinking no pressure was available)

i do have a code for the Nissan Maxima Vapor Canister Purge Valve that needs to be replaced and knock sensor code, could those be the problem?

any help or suggestion would be appreciated

 

yes that is how you test the alternator. the brake light coming on is when your alternator has COMPLETELY **** a brick.

 

im also pretty confused as to what youre saying your actual problem is?

 

It sounds more like a misfire which he think is jerking but he has other problems as well. For the car to cut off when you placed it in R to park, indicates something may be wrong with idle adjustment.

 

Do what everyone else has suggested, and have the alternator tested by an actual charge/start tester. The voltage can be fine, but with you stating that you heard a whining noise the other day and it went away.....one of your diodes could be starting to give in the alternator. Charge/Start tester will let you know if the diode ripple is abnormal or not.

 

If it's jerking while driving you might have a bad coil pack. Pull each one, if idle changes it good, if not that one is bad and change it.

 

My car was doing the same thing last night while i was driving dwn the interstate, and i was like, wat the heck is that making it jerk, but i will check the coil packs and see which is bad, going to the junk yard in the morning

 

Consider MAF and TPS too.