Not on my own Elgrands but on customers..
Yesterday I did this with an E52
https://elgrandoc.uk/forum/threads/vibrating-in-gear-standstill-low-idle.44757/#post-641352
I also had an E51 delivered to me on the back of a lorry by a forum member. This is one the owner had me convert to LPG years ago but from the day he bought the Elgrand he said it occasionally put the engine warning light on with error code P0350 (supposedly pointing to a duff coil pack) though it didn't seem to effect how the car drove, no misfires or other symptoms. In attempt to stop the occasional P0350 error code the owner tasked a garage local to him with changing all 6 coil packs but the garage only managed to change 5 coil packs saying they couldn't change one coil pack because 'LPG stuff was in the way'. Heh all they had to do was undo a small clip on a narrow diameter low pressure rubber gas hose (which as an injector outlet pipe so open to atmosphere so had no pressure or gas in it anyway) and they could have changed the coil pack easily enough, the mechanics won't have any qualms about disconnecting much higher pressure petrol pipes or hydraulic lines on vehicles so I don't know why they'd be concerned about disconnecting that little pipe... After the garage's attempt at changing the coil packs the car ran rough, so the owner thought it better to have it trailered to me than to drive it to me in case of a big problem such as a cat failure (which I could better diagnose and probably cure than the garage). The owner also wanted me to change the last coil pack that the garage couldn't/didn't change and have me change the spark plugs while I was at it (if changing the coil packs might as well change the plugs while at it if they've been in there a long time or have done a lot of miles).
The car arrived with me earlier than expected so I had a quick look at it last night and had the misfire fixed in 5 minutes lol. I used NDS2 to find which cylinder was misfiring using the cylinder power test, it was #1 cylinder. I switched that cylinder to run on LPG to see if the fault went away (which could point to a clogged petrol injector on #1), the fault didn't go away. I switched all cylinders to LPG and turned off the petrol pump (if the fault went away now it would point to a stuck open #1 petrol injector), the fault didn't go away so it was looking like an ignition fault. It seems the mechanic tried to change the coil pack on #1, partly removed it (at least slackened it's securing bolt) but either lifted it then didn't reseat it properly so the narrow end of the pack wasn't on the plug or just didn't tighten the bolt up enough so the contact spring in the pack wasn't making contact with the plug. I removed the old coil pack, changed that plug while I was at it, fitted the final new coil pack, and all the problems went away. Then I removed all the other 5 coil packs, changed plugs and refitted those 5 new coil packs. #6 Coil pack bolt was loose too, I expect even if there wasn't a misfire on #1 cylinder there would have been problems with #6 misfiring soon, the garage can't blame LPG stuff for being in the way of #6 coil pack but there is a Nissan bracket a bit in the way for #6 coil pack on 2.5's like this one.
Just about to do a test drive then give the owner the good news.
Got another well known forum member coming for plugs change and flaps threadlocking tomorrow.
