I've probably bypassed a few threads about this but I feel as though I should ask anyway. When I start my Z cold, for the first 30 seconds, minute, 2 minutes, depending on whether I let it warm at idle or just start driving slowly straight away, it seems to run on only 5 cylinders. As soon as it warms up so the needle gets about half way up to where it runs at normally (half way) so a quarter of the gauge, it will stop and run smooth as ever. My Dad is a mechanic and he immediately thought it could be a dodgey or slightly blocked injector whereby it doesn't work properly when cold. He said it's worth asking you pros. Please ask me any questions to help you answer but I would like to get this fixed and gone ASAP!
Is it running on five cylinders or just running rough making you think it is? If it is one lazy cylinder you should be able to identify it so then you can start swapping coil packs, spark plugs and re-tensioning the connecting plugs and see if you can identify it. Are you running a Type 1 or Type 2 PTU? Borrow a spare PTU from someone and try that. But the main culprit would be the air regulator which controls the cold start process. There are lots and lots of won't Start, rough idle on Start threads. Search is your friend.
First thing I'd do is isolate which cyclinder isn't working when cold. Easiest way if you don't have datascan etc... is by unplugging a coilpack connector one at a time to see if there is any difference to idle.
Hey I havn't got a Datascan yet but I've purchased an ECUTalk cable, am awaiting it's arrival in the post. Will be pulling the car out today to get started on changing radiator hoses so I will do a pull-plug test if it comes to mind! Cheers guys. Will let you know the result.
