hello everyone

I have 03 350z with single turbo setup. (turbonetics)
255LPH walbro stock fuel rails
GTR Injectors
GT30 TURBO
Plenum spacer
Uprev tuning

Problem is : Car Drivers perfect on high revs, but on IDLE after 2-3 min standing afr shows 14.7 and then suddenly it goes lean. 15.0-15.5-16. Code P0300 Random missfires and burcks from exhaust .
Upstream O2 sensors correct all time 100% 105% 110% 120% ..

New sparks, coils perfect, MAF ok, no Air leaks checked with smoke.. I don't know what to do..

 

Does your tune have a cold compensation where it increases fuel before the car warms up?

 

it happens when cold when warm when hot after drive, as soon as car stopps and idles it rendom misfires and leans

 

If you keep the a/c on does this problem still happen? What's idle RPM?

 

ill try...

RPM under 1000 . 700-800 i think

above 12000 its getting ok as i giving rev, but under its leaning

 

nothing still same...

still changed plags, all colis perfect injectors tested ok, no leaks,
leaning at IDLE and missfires

 

It's either tune or fuel related. Double check your injectors/get them flow tested and cleaned. To me it seems like one or two could be sticking at idle.

 

CHECKed ! they work

 

How exactly did you check? Did you send them off for a professional cleaning and flow testing service?

If not injectors you might have a fuel pump issue.

 

I changed my fuel pump and its bucket with stock fuel pump and stock bucket same happened ...

what about fuel injectors.. i removed them all switched car end its working non of them leaks or opens .. so now i want to install stock injectors and see whats going on..

 

any ides everything works fine camshaft sensors crank sensor all .. still leaning at idle and misfires..