350z has no response for accelerating. Problem is coming and going and now it all the time. Changed fuel pump mass air flow and throttle body. Has no code and Nissan dealership said it was the exhaust resonator. Change it no good. Anyone one with an idea

 

what did you recently change before this started happening.... what year... why are you just throwing parts at it?

 

It a 03 65k miles. Didn't change any parts it just started acting up and got worse all the time now. Throwing parts because it has no codes.

 

no everything throws codes. i would check for a vacuum leak on the intake. you are (assuming) a new owner, if so what all did the previous owner do to the car? plenum spacer anything like that?

 

Yes checked for vacuum leak. It's all original. When you nail the gas you can hear it breathing but takes off slow

 

is it true limp mode, wont go over like 2500 rpm... or just real bad hesitation? could have clogged cats, but low mileage

 

Dealership said cats ok. How do you check cats. Does this car have a true lump mode.