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Discussion Starter · #1 ·
I mentioned I'm also having this issue in a post about my clutch. I was asked to give details about my lack of power and here's what I said:
"The running problem I'm having is tuff to explain... At first it wouldn't rev past 3,500 RPM. Then as it gets warmer under the hood(not coolant temp. That stays good) it'll lose power at a lower & lower RPM. At first I can cruise as high as 55, then it's hard to even hit 20.
In trouble shooting this; I replaced the vacuume line that plugs in right in front of the throttle body. Now in neutral I can rev it up all the way, but in gear (under load) I have the same problem.... Any thoughts?"
That's my issue. I can put around town slowly, but can't hit the highways. Anybody know what has gone bad? Should I replace all my lines or something? It's a 280ZX by the way

Thanks
 

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1983 280zx n/a 5-speed t-tops
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57 Posts
Just a couple things to get the discussion going: have you/can you check timing - ensure timing advances properly with RPM. Check vacuum and vacuum response with RPM. Check operation/condition of the cylinder head temp sensor. Is the car equiped with california of federal emissions? Each has several vacuum operated devices. Theres also an altitude switch that affects the ECU but I dont think you should be affected by that.

Or, could be in the fuel system. Check fuel pressure under different RPM. Fuel restrictions, blockages in the fuel or evap/vent lines. Check fuel pressure regulator operation under vacuum.

Thats not all but should give more clues.

Can't remember your experience with the S130 so let us know what you find or need help finding.
 

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1981 280zx GL na 5spd
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18 Posts
If your problem is fuel related I would recommend checking out the fuel sending unit in the tank. My 280zx was sitting for a few years before I bought it and the sending unit tubes were completely blocked with a thick black gunk (probably dirt mixed with the varnish fuel). I'm assuming this is something that just happens to these cars after sitting, worth checking on it if your Z has been parked for a looong time
 

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Discussion Starter · #4 ·
My Z has not been sitting for a long time. In fact it used to run great. This problem just trickled in... My buddy Guy (Z Doctor) said he suspected it to be either a seal break or a clogged exhaust.
To test this I sprayed Starting fluid all over the air intake system while idling and disconnected my exhaust under the manifold. There were no changes in idle and no driving changes so intake or exhaust don't appear to be the issue... The fact that in neutral it revs ok, but not in gear; makes me think maybe it's a vacuume thing.
Please keep your thoughts coming. I miss my Z 😢
 
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