mr v6

Sounds like you need a full 4 wheel alignment / geometry check.

Mine was a pain, the slave cylinder went & was replaced FOC by the garage I bought the Z off. I supplied a HEL braided line to go on. They said it was a nightmare too, something to do with the square valve block thing behind the NSF wheel arch liner. I still wasn't happy so bled it again on the drive & it's been right as rain for the last 8 years.

Have you scanned it for any codes, pending in particular? I've had coils that were starting to go & were affecting drivability but hadn't put the EML on. I've had coils that have turned the EML on. I also found a throttle body clean & perform all the resets on here helped with my idle issue too.

Try 755B0CD000. That fits up there & attaches to the lower right bumper corner piece underneath.

I'm 99% sure this is exactly what I pulled off mine about 6 months ago, along with the small black lower bumper corner piece. I'd read online it's the evap canister shield, but I could be wrong there.

Could be a number of things, like a stuck closed thermostat, failed water pump, clogged radiator, seized cooling fan motors are very common on the Z. Do they spin when you turn the aircon on?

I've used these people in the past for refurbed Brembo calipers & pistons: https://brakeparts.co.uk/shop/Nissan/350z/03-/350z 3.5 V6 Petrol/Rear - Brake Calipers and Wheel Cylinders

Weeks after getting my 2005 Z 1i had an annoying ticking. My fuel dampener also ticked & was convinced it was that. I was ready to order one. I just pressed down on each of the ignition coils on the drivers side (not sure why, i was just messing about) & found the noise went. My issue was x1 spark plug not quite tight enough. My ticking also went up with the revs.

Odd, as my drivers side is auto up & down as per the 'A' on the switch, but the passenger side is not auto up or down. I'm sure that's how they are. I did read on here a few years ago that getting a drivers door switch with both switches being 'A' auto, meaning both windows are auto, but that left the switch permanently live once the ignition is turned off.

If you're doing the clutch it makes sense to do the flywheel too whilst you're in there. If you buy a whole kit with a lightened flywheel then fool proof it & do it all. Your spongy pedal could also be the rubber line going to the slave cylinder outside the box, go for a braided one. Mine had the Xtreme kit fitted, stage 1 I believe from the previous owners invoice & it's been great. Pedal is heavy, but I've not driven another Z so have nothing other than previous cars to compare it against. If you use it as a daily then you don't want something too grabby as it'd be awful in slow moving trafic.

I need to replace one of my compression arms, but I'm a bit wary of having a go in case one of the chassis studs snap. Just how common are these for snapping? I'd rather have a backup plan in place should it happen. Is there anywhere close to M31 postcode that could not only replace it (easy to do I know), but also repair it if needs be. I've seen a Lee Lockwood video on YT & he had a welder go to his house & weld a new section of thread onto his & it seemed fine.

I was in a similar situation many years ago. Bought a car, hyrolocked the engine, insurance paid me what I paid for it & gave me the car back. I put another engine in it & it was fine for another 9 years till I scrapped it. Don't accept their first offer. You've nothing to lose by being a bit cheeky.

Without stating the obvious, have you looked on Youtube as there's plenty of US videos that should help you out? It's quite straight forward. Only awkward bit is making sure you don't drop the J hook & it's nut down the back, other than it's just the plastic upper covers that need to come off 😁.

Make sure your battery connections are tight! I had this exact issue a few times when I first bought mine, clocks would light but, but nothing on cranking, try again & it was fine. Turns out my battery connections were not tight, nipped them up & the issue went away.

Fuel pump seal ring worn along with other parts are a possibility. Could be a very small leak & it evaporates before you get chance to see it. Get a garage to smoke test the tank through the filler neck, should be easy to spot then.