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G'day.
I bought a 2003 manual 350z track (100,000 miles) a while back and it had this issue when I bought it - I thought it would be an easy fix but it turns out not.
The car pulls fine to approx. 3,500 rpm and then it was like hitting a brick wall - it just did not want to pull through that.
Mechanic number 1 - advised no codes. New plugs fitted. One new coil pack fitted. New MAF fitted. New fuel pump and assembly fitted. Electrical connector fixed on one o2 sensor - car still ran the same.
Mechanic number 2 - advised no codes. Had it on the dynatune for some time. Replaced fuel pressure regulator. Car runs a little better but at 3,500 rpm instead of hitting a brick wall it just slowly ….very slowly wanders up through the rev range. He wants to do some expensive mod on fuel pipes and fuel rail. I understand that may deliver more fuel but am concerned the underlying problem may still be there.
I don't know an awful lot about cars (my son does although he likes his S13, 14 and 15) and really don't want to take it to the one Nissan dealer within 2,000 miles as I have had a bad experience with them before so was hoping someone might have some suggestion of what to look at next.
 

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Sounds like a transmission or brake sensor putting her in limp mode. No slip light showing? May be burned out light in the dash for the indicator but I’m almost positive that’s what is happening.


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Update - took her into the local Nissan dealer. They had her for 2 days - and have no idea whats wrong.
Since getting her back home have changed the 2 cam sensors and the crank sensor - no change.
Was thinking of changing the oxygen sensors next
 

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The only thing the dealer did note was the plugs had a brown deposit - and asked me if I had been using an octane boost. I havnt and the plugs have done less than 500km.
 

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The only thing the dealer did note was the plugs had a brown deposit - and asked me if I had been using an octane boost. I havnt and the plugs have done less than 500km.
brown deposit on plugs vs octane boost ? what kind of dealership is that ? go somewhere that hires true mechanics. Mechanics that known that brown deposit is normal on plugs.

What is the battery voltage ? does it changes wildly when reving the engine ?
What oil are you running ? and does oil pressure goes above 60psi at 3000rpm.
3500 rpm under load is when the intake cams are being advanced. did they run a dyno or street run and see if cam timing is responding ? you might have over advance if the oil is too thick creating compression strokes issues.

Is the ECM flashed or oem ?

Get the car to someone that knows how to diagnose EFI engines. It will be hard to do that online. Sorry I didn't help.
 

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I ended up changing cam and crank sensors - no change.
Changed fuel from 98 to 95 octane - ran slightly better so I let the wife drive it. After a month it broke down and threw an error code for accelerator pedal sensor - changed it, no difference.
That did get me to thinking about the fuel system so yesterday changed throttle body and did an ecu reset..... SUCCESS.
While I think the ecu is still doing a little bit of learning, the car is running almost perfectly.
Thanks to those who posted with suggestions.
Happy wife...….happy life!
 

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Good thread and even better that you capped it off with a SOLUTION to your drivability problem. Congrats! With USDM Zs, I've never seen a VQ get stuck at 3,500 RPM limit. Even in limp mode, it barely creeps above 2K and there's always a code (or two) stuck in memory. Where are you located? Oz?
 

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Correct, Darwin in Australia. And that was some of the problem. A city of less than 150,000 people and some 3,000 km to the next city. Try finding a specialist that can work on the car (even the service advisor at the Nissan dealer privately said to me if you find out what it was would you let me know).
To be fair, the 3,500 limit was a bit like a wall, but the car would go through it, just painfully slow. It basically just stopped pulling at 3,500rpm.
It never was in limp mode and I figure that all the mechanics need to see error codes - they have lost the old fashioned skill of thinking through a problem....bit sad but the modern way I guess.
 
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