Okay well recently purchased a used g35. It just turned 134k miles. When I bought it it had a hard time starting usually takes 2-3 times to start the car and when it does usually sputters the. Seems to idle okay at times and other times feels like a dead miss. When I started the 600 mile ride home I had a check engine light come on and stay on the whole drive. So when I got home I pulled codes and ended up with p0171 and p0174 both banks running lean so my initial thought vacuum leak. I have sprayed carb cleaner / brake clean around my engine, intake ducting, everywhere around the motor to my avail no change in idle. The engine light since then has gone off on its own indicating not a hard set code so intermittent running lean condition but upon live data I can still see it's running lean on fuel trim. I have cleaned the maf as well thinking that might be the problem but has not helped. The idle will fluctuate anywhere from 1k rpm to 500-750 it's never really consistent. I was curious if anyone has ran across this problem that can point me in the right direction. I planned on having the car smoke checked in the next week but would rather try to narrow the problem down. Sorry for the long post and thanks for any help anyone can give

When you try to start it does it feel like its has enough power? Does the starter crank strong? If so it might be the fuel filter/ fuel pump.

Yeah it cranks more then okay battery is new nothing wrong with the starter it will just sit and crank unless I stop and attempt to crank again and then it may start. I was thinking the same thing possibly a weak fuel pump but drives normal once it starts driving down the road no problems but can hear it start pinging upon occasion, predetination problem obviously from running lean. I know the regulator is built in the fuel pump was suspecting this as the culprit possibly blessing fuel pressure back. I think I may start with a pump but having trouble locating one for a sedan all of them I see are for coupes only what did sedans fuel pumps become bulletproof lol

Rockauto.com
They will have the right pump.

I purchased a fuel pump so hopefully going to get a chance to throw it in tomorrow and see what happens. I did look at what you suggested by all were for coupes only can buy the pump itself and not the module

i would suspect the fuel pump. i have an old chevy truck and it would take a couple tries to start. the pump finally died and since i changed the pump it starts immediately.

Before you start throwing parts ($$) at the starting issue have a Nissan authorized mechanic check the problem out with his gauges!
Gary

Like testing the fuel pump pressure and checking the injectors

Telcoman

We'll have to come out and just say it !!! Kudos to Infiniti that had to be the easiest pump I have ever done lol. Starting problem fixed which I'm pretty darn pleased about. I got into the original pump and it wasn't even together correctly bottom half of the pump cage wasn't even secure to the top half lol looks like someone didn't know what they were doing lol.

Guess now the only thing left to do is hook back up to my scanner and see what the fuel trim is doing thanks guys for your help