This 350z has been boosted and blew the moter but it has been replaced with another vq35de and was running fine for about 2,000 miles and just started not running rite for no reason. If you accelerate slowly the rpms will rev up but if you rev it up fast it will not rev up it just sputters . We have checked the mass airflow sensor and the throttle body and it is working fine. also if you cover have of the end of the intake pipe it runs good. anybody have any solutions?

 

I had a issue like this with a Supra and it happened to be fuel related. Is the PSI on the fuel pressure keeping up with the needed delivery? How old is the fuel pump?

 

the fuel pump was upgraded when it was boosted so probably 3 months old. but i did notice when i turn the key on after it sit you can hear the fuel pump come on and then if you turn it off and right back on it dont come on. i dont know if it could be its still pressurized from running before. does this sound normal or should you hear it running everytime key is turned on.

it take a few times to get it to start and then it idles real low like maybe 200-500 rpm and may die a few time but then finally it will rev high then level out to normal. but if you give it gas fast it want rev up none. the exhaust will sputter and you can hear engine gasping air. but if you slowly barley give it gas it will rev or if you over up have of the intake tube with your hand it will rev just fine.

 

anyone have any ideas before i take it to dealership

 

Sounds like a sensor issue to me. Check your exhaust and crank sensors.

 

also there's no check engine or service engine lights on on the dash.

 

Check the fuel pump again. I know it's new, but it could be bad. Just because it sounds like it's working doesn't mean it's pulling enough fuel when under a hard load like revving up fast. The light load of revving slowly may still be able to get enough fuel.

 

it was the fuel pump. thanks for the help

 

Glad it's fixed. Thanks for the follow up.