Okay so basic information first.
I drive a 2007 infiniti g35x sedan, vq35hr, automatic, rwd with switch awd sedan.
here is the problem i am having,
so basically i did the spark plug change a couple of weeks ago. car runs fine no misfire or anything except there is like a drop in rpm at like 1000-1500 rpm only when the car is hot and only when the transmission is engaged. meaning while its in drive or reverse only. and only happens when the car is hot.i took the spark plugs out and installed it again and all i just cannot find this issue online and the mechanic near me doesn't know ****. Car runs fine and pulls like a beast. except that issue is just driving me crazy also it only happens in low rpm in that range only....

 

Did you TORQUE the spark plugs? Did you use OEM plugs? Did you perform an idle recalibration (needs to be done with the engine hot)?

If your mechanic is useless then take it to the Nissan dealership for a diagnostic, it's their car, they can tell you EXACTLY what the problem is then you can decide how to go about the repair. Hourly rate between Joe Mechanic and Nissan is usually the same $125-150/hr and Nissan has a flat diagnostic fee usually, drive by and talk to the service department.

 

I ddi torque the spar plugs to 220in/lb. I did use the denso iridium oem plugs as well. And no i did not perform a idle recalibration. How do you do that???

 

http://www.nicoclub.com/archives/g35...procedure.html

Use a watch to count seconds, it has to be very precise. That link is a little easier to digest than how it's described in the FSM but the FSM does have a nifty little diagram on page 18,19 that helps explain it for the more "visually oriented" folks.

http://www.nicoclub.com/service-manu...7_G35_Sedan/ec

 

do you think it can be that? i will try it and let you know of the results