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Discussion Starter · #1 ·
at a certain rpm range my Z sputters and loses all power until it reaches around 5 to 6k rpm and then it goes back to running ok. (1983 280zx non turbo)


In these 2 videos, my throttle is in the same spot the entire time. I've gotten new injectors, distributor cap and finger, spark plug wires, and sparkplugs. any help would be appreciated.
 

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it certainly does not sound like its unmodified, (or maybe just a giant hole in the muffler.
Has it been modified from stock?
 

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well is sure sounds like it nees exhaust work, that being said I would start with the basics, get the FSM start checking things like fuel pressure, timing, look for vacuum leaks etc.. The FSM is the way to go esp since its all stock.
 

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Discussion Starter · #5 ·
its fully stock the only thing "done" to it is a cat delete
there is a tiny hole in the downpipe so that's what is probably causing all the exhaust noise
well is sure sounds like it nees exhaust work, that being said I would start with the basics, get the FSM start checking things like fuel pressure, timing, look for vacuum leaks etc.. The FSM is the way to go esp since its all stock.
 

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Discussion Starter · #6 ·
vacuum is up to speck fuel pressure is perfect right at 35 I don’t think timing would be a issue since it’s only when the motor is hot
 

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any other suggestions?
take it to someone that knows Z cars. 8 second clips and statements like it runs "ok" at 5-6k is just not enough details to diagnose remotely.

example
how does it idle
what the compression numbers
have you confirmed the firing order
have you done a power test
what do the plugs look like, use them to read the AF mixture
what are the readings of the temp sensor resistance a the ECU and at what engine temp
whats the vacuum at idle, is it steady.
does the FPR react to the vacuum as it should.

It should be running GREAT (smooth and lots of power) at 5-6k if its just "ok" then its prob still not right but being masked by the higher RPM with less load thru the gear box.
 
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