CCooperTech

Yes I've replaced both CPS with oem sensors and that particular set of problems have resolved.

Yes it does, and funny enough I couldn't get it to do a throttle position re-learn. With the flutter at 1800 revs maybe you're onto something

I said I'd update after a few days... No more CPS issues, and a nice clean drive, although the revs between 14-18K are hunting a little and it does seem to sit a little high at idle. The P0420 fault is back now though, took a few days but it popped so I guess I should start looking at a replacement cat. Thanks for the support all.

I guess it was a little obvious, as I just did that today, but good advice none the less. I also had to replace the connector on bank one. It took both of these actions and triggering an ECU re-learn to solve the issue... At least I believe it's solved. I will update after a few days with hopefully no issues. Thanks for the reply.

Hi Beb, Thanks for the response, but the P0420 has stopped with the start of the P0340. Based on the fact I am getting readings of 63.5° degrees solid, no fluctuation, on the CPS I am pretty sure its related to the CPS or engine management, not the coil pack.

Hi all, I'm appealing for a little knowledge from the experienced folk on here. I have had some engine management troubles over the past couple of months. It started out as p0420 faults. All actual values (on my diagnostic kit) seemed ok though so I was starting to suspect a failing cat, but at just 66k that seemed off. I decided to let it develop... And it did. P0340 with the ESP and traction lights. Power cuts momentarily then back to driving. Hard to start when warm. Great I thought and fitted a new CPS. no difference. Actual values at 63.5° with both the old and new CPS. However I don't get the P0420 anymore. Anyone any idea what could be the cause and where I go from here? Forgot to add the car details: 2003 350z 66k miles on the clock, mostly original setup excluding a k&n typhoon induction kit. Does have an lpg kit fitted, but the problem happens on the 99 octane and the LPG.

Hello! and thanks for the detailed "detailing" / cleaning post. Think I will have to give that a go when I get some free time. Looks lovely, and the car park pic is very nice.

Hi Chris, Lovely looking Z, and in Merseyside, I'll be keeping my eyes open to see you out and about. Good Luck on the clutch.

@marzman Hi, the LPG kit was already fitted. Performance wise, on the road there is no noticeable difference when I'm on 98 octane petrol, to when I'm on the LPG. The sound at the exhaust is kind of smoother, less rumble than on petrol, but otherwise really no difference. No idea if that would be the same on the track. Mileage is pretty good. Under normal driving I'll get 24-25mpg on petrol and about 21 on gas. The tank will run me 170 miles at a cost of about £16-18. You do loose all of the boot between seats and strengthener to the tank though. They also did a lovely job of hiding the filler behind the number plate, so it's not visible from outside.

As I've been lurking around doing allot of reading of old posts I thought it about time I said hello. I'm Colin, I live near Chester and work in Liverpool, so the Z is regularly between the two. I've got a 2003 350z GT, had it a couple of months now. 64k miles in very straight and clean condition (with the exception of needing a cat). A couple of mods were already on the car, nothing too adventurous though... except the oddest one of all, a well fitted LPG conversion with valve oil injector and a remap. As odd as it is I'm loving the gas though, as commuting in the Z is quite enjoyable, and now affordable.