Story time but you don't have to sit Indian style and sneak peeks at my chest
 

So..here’s the scoop on my first 350Z adventure.. I bought this thic whip with no paperwork. The shop that did the mods let the mechanic work on it "off the books" No paperwork there either 🙃 I’ve got a dyno video from the shop showing 501 wheel.. courtesy of a Vortech V1 T-Trim supercharger! The car had been barely driven for almost a year..only getting a workout with some idle warm-ups and the odd grocery run. The previous owner finally came to terms with no backseats for his kids and we struck a deal. I drained the old gas..filled her up with fresh fuel..and began taking short trips to the store. Slowly but surely..she started feeling sluggish. 😩 On one of these trips.. the AC blower quit. I thought.. No biggie, probably a fuse. A quick trip to the parts store and a new relay later..the blower was still out of order 🙄 Then..a bigger issue popped up..the car refused to rev past 3,700 RPMs. Checked the fuse panel..checks out. On the drive home, it got even worse, struggling to hit 2,000 RPMs. By the time I pulled into the driveway, it was clear something wasn't happy 😤 Next day..it wouldn't start. Just cranked endlessly. A few days later..it started but barely idled..sputtering like a elderly man with a blue tie getting handled in a debate. Now..it’s a gamble if it even starts. So here I am..left with the pieces of a puzzle that’s missing half its parts. Local shop wants my left kidney or $1900 to diag and retune.

Have you tried pulling the codes?

What's the local shop? Where are you in NC?

No CEL or SES
NO codes on scanner
Local Shop is the only Pro Tuner for UpRev in my area
Charlotte
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If you're going to attempt to fix it yourself, then start with the main 3 requirements (air, fuel, spark) and work you way down from there with troubleshooting. It sounds like a fuel issue, but the other symptoms you describe could also point to a bad cam/crank sensor which have limited lifespans. In all honesty, there is really too much for anyone to diagnose over the interwebs without laying hands on it. SOHO may be expensive, but they definitely know what they're doing.

If there’s any confidence in the tune (it sounds like the car ran), start with your list of car-has-been-sitting and regular z33 troubleshooting. Some suggestions:

- Replace spark plugs, probably a step colder than stock for your application.

- Check ignition coil resistance and replace any bad ones.

- Check cam sensors and the crank sensor. It’s a classic Z33 crank-no-start culprit.

- Does the fuel pump prime? Is there an aftermarket fuel pressure regulator somewhere to raise pressure vs boost using a reference? Is it set correctly?

- Clean the MAF.

- Check the upstream O2 sensors.

Hope you get it sorted out.

Update🗞️
All signs pointed to a fuel pump failure..so I slapped in a new replacement Walbro 450..and she’s humming strong 🤤 though I'm having a few hesitations on wot but it clears up on its own. Bought a new blower motor as well..now we’re blowing air again...but it's hot air because ac compressor isn't kicking on. The tune is still a bit iffy..with rev spikes between gear shifts.. Could it be a vacuum leak?