ok guys like i said in the other thread there is a ghost in my car....

well today i thought my car was all fixed of the misfire thing well here is what is happening...

when the car is warmed up and been driving for a while the car starts to misfire....only under load and when warmed up.......i am throwing up a 0201 code....which has to do with the ignition misfire...but its not throwing up the other code to tell me which cylinder....there is also a hissing type of sound coming from like under the manifold side near the iavc aswell but i cant find it...i have sprayed throttle body cleaner all around that area to try to see if the rpm will jump up if its sucking air from anywhere and there is nothing....i cant see under the manifold and i dont know if there is a crack in it or not...but there is definatly a hissing somewhere but i cant pin point it....i think this may have to do with my misfire BUT why is it only doing it when warm and under load??? if it was a vacuum leak wouldnt it do it with or without load??? im very confused and i think i am up for alot of dollars....

When its misfiring whilest driving.....it will drive but misfire...it will make my rpms jump up and down and if overdrive is on and i am driving at a low speed and overdrive kicks in it will be say at 1500 and then drop to 1100 and start to misfire.....

now i if i unplug each coil they all do the same thing...slow the car down.....

things i have down to try to diagnose and fix it...

1. i changed all the spark plugs...thought this done it...nope
2. i have checked on the resistance ohms on the coils..all are the same
3. parked the car in the garage till i can figure it out
4. borrowed my mates jdm pulsar (which i built) while i get the maxima fix or i fix it

 

Do what you know. My bet is on one of the gaskets leaking since you removed the manifold to change plugs. I always fix what I know is wrong, in your case you hear a vacuum leak so you need to find and fix it first.

 

and it might not be misfiring...it could be backfiring...i can feel it pop when it does it.....and the motor like rocks back and foward....

 

i put all new gaskets and the car ran fine for 3 days before this started....i have a small oil leak aswell that looks like i think is dripping onto the crankshaft position sensor from what i can read the crank shaft position sensor can do what it is happening to my car....like i said its only doing it when the car is warm and under load....

 

and the car was already misfiring/backfiring before i changed the plugs and its a vq30de...i dont have to remove my manifold to change the plugs