I have a 08 infiniti g35 sport sedan 6spd manual, the car is having a little problem, when I drive the car and I reach to 3rd gear the car stops at 3k rpm and rises slowly to go up higher. This just started happening today, can anyone help me figure what the problem is before I get charged double the price what it should be???

 

Only happens in 3rd gear?

 

it starts from 3rd gear and stop once I reach to 5th gear

 

Since the car doesn't even know what gear you're in (it knows when you're in neutral and when you're in reverse, that's it) I strongly doubt it's a transmission issue. If it starts doing this try shifting straight to 5th gear and see if it's still persistent. If so slow down to 2nd gear and see if it goes away.

I suspect it's a fueling issue that's only showing up when the engine is actually under load at higher rpm. Once you're up to 5th/6th gear you're probably traveling fast enough that the engine doesn't need to rev out and you're at a lower rpm. In 2nd it's probably there but you are having a hard time feeling it due to the aggressive gear ratio in lower gears, 3-4 is where you're actually pulling under load and the engine is working the hardest before cruising again in 5-6.

Unfortunately there is no fuel service port on the VQ, you have to add a sandwich adapter to the fuel damper like the one sold by Z1 Motorsports.

You could always pull the fuel pump and see if the strainer baggy is covered in debris.