I'm at my wits end with this thing :p I'm probably just going to have a shop look at it, because if I keep working on it and having the same issue, I'll get angry and sell it.

So, 280z, stock l28e... A few months ago I'd been having an issue with it bucking, going on and off power and clunking along, and having the idle go crazy, between 500 and 2000 and back and forth again. The engine lacked power, and when I took my foot off the gas, about three seconds later the car would sort of clunk, and I'd occasionally smell gas.

I replaced every vacuum tube (a few were broken) in the engine compartment and a bunch of fuel lines on the rail, replaced the clamps... I had an issue with difficult starting that I rectified by finding another vacuum tube which was broken, and replacing that.

...so the car ran PERFECTLY for about a month, and now... I'm back to all the same problems as before, including the gas smell. I've checked all the fuel lines, re-checked all the vacuum lines, and I just feel really futile right now...

...My significant other and I just bought a nice z31, but until my car is sorted out, I'm in no mood to brag about it/post pics.

Any ideas as to what this could possibly be? Bad ignition? Bad vacuum advance? Bad fuel pump/pressure regulator? Or, its off to try either Shinzo or Mike's z Shop. It just kills me that while I can find no difference in the engine bay between now and last week, when it was perfect, I have the exact same problem as previously.

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If your car had carbs, I'd say you have a bent throttle shaft and the butterflies aren't closing. Since I'm pretty sure your car has FI, I'd guess a bad injector.

Will

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1969 Datsun 2000 (track car, driven daily)
1959 Alfa Romeo 101.02 Sprint (big project)
1969 Alfa Romeo 105.51 GTV (R.I.P)
'87 BMW M3

Have you checked the big rubber tube between the throttle body and airflow meter?

not the problem mr roper.....the issue will be your CHTS, cyl head temp sensor, its the pricey little bugger on the front of the thermostat by your $15 water temp sensor.

That should fix your issue, but its probably best you check the wiring going to it and find one at the junkyard or swap one off of a good running car, if you decide to buy one new (around 150-200 last i checked). Hope that helps as ive seen this and actually had it happen to me once. Also sign up over on hybridz.org....alot of info on that site but please SEARCH and you will find almost anything you could possibly want to ask.

Thanks for the advice all, I just have to step back from the issue for a while, whew, I take my car too personally.

It's hard for me to feel like wasting ~$150 replacing sensors blindly if I don't really know how to test if they're bad in the first place, so I'm pretty ready to leave that up to the care of professionals and their judgement Ugh.

I am 90% sure the fuel injector o-rings might be somewhat gone... A few of them seem to budge/wiggle with little effort. I might at least try doing that myself first, and that would account for intermittently smelling gas...

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Check your dist. cap for cracks.

the chts is a good place to check since the old efi sysstems just had 4 sensors to manage the fule ..1 the t.p.s. 2 a.f.m. 3 c.h.t.s and 4 crank signal ... the chts is a big part cuz if it gets unpluged the car will stutter and die it also dicides how much fule it will use at cold and hot operations .. to check it or how to check it you can look in to hains manuls from 77 810 datsun and efi 280zx. they have a boiling water test ...