So the car has been in the shed for a few years but I have used the lock down to get her back on the road with Historic plates which is cool. But it has an intermittent miss which is making life un-fun. Thinking injectors but unsure of how to test them on the car or if I should just rip them out and replace. Has anyone had any experience with the less expensive ebay injectors as I'm not keen on dropping $5-600 on a set.
Have you checked simple things like plugs? Checked for ECU codes? Pulled coil pack connectors to see which cylinder is miss firing?
ohm test the injectors and coils, check power to the both at the connectors. like IB simple things first.
Intermittent miss during idle is a common complaint on Zeds that haven't been driven for a long while. Does it drive OK or does it run raggedly and misfire when you're driving it?
It could be a sticky injector. You can identify which one by pulling one coil pack connector at a time and listening for a drop in revs. Second hand 'series 2' injectors are fine as long as they are 'genuine' for piece of mind. For example Jatco have the 'J' or 'JC' logo stamped on the side of the injector and a number. I forgot what the logo looks like but you can search online for Genuine and see a picture of one. Plenum needs to come off but that can be a good thing. Once off the vehicle, it can be ground in certain areas around the injectors (have a look, its obvious) so that in the future the injectors can be removed without the plenum having to come off!! I wish Nissan did this in the 1st place. Also, can remove the small water hoses, or replace them. Can tidy up the plenum underneath and it's much easier to take off in the future. So many improvements can be made with plenum off. If the plenum is Series 1, and using Series 2 injectors, you will need injector adaptors, get them from Z1 Motorsports. Perfect quality. If the injectors you intend to use are second hand, get them serviced and flow tested for even volumes and check spray pattern. Also use 'viton' seals. Viton seals are bullet proof for this application. Also replace the pintle caps 'plastic pintle protectors' with new. If they are old, they can split open and compromise injector bottom seal and fuel will dump into cylinder. Use 'viton' seals wherever possible only again for piece of mind because they are a little harder than the standard butyl nitrile ones and can handle higher temperatures and fuel much better. They are expensive though. That's all I can think of.