Did some more maintenance. Finally got around to tackling the spark plugs, I had read that the intake manifold would need to be removed in order to do the right bank, but on the GDI turns out just the throttle body needed to be removed. When I got the truck I ordered spark plugs before it showed up, then when it got there I realized I needed a throttle body gasket, just looking at it as the throttle body would for sure have to come off. So I ordered that, when that came in I looked at a how-to and people were talking about removing the intake manifold, so I ordered the plenum gaskets, when those came in, I finally got around to tackling it... over a year later. The truck still had the factory spark plugs, which at this point are 21 years old and had 119,000 km (FSM wants them replaced every 80,000km). I am likely going to block those EGR valves and see what it does. Being old, and GDI, the throttle body was pretty clean, but the back side of the throttle plate and inside the intake manifold had some carbon build up. I have been using a can of sea-foam top end cleaner at every second oil change, and that has made some impacts you can see, but at this point I might try and get set up to do walnut blasting and take the intake manifold off in the summer, and inspect and blast the valves. Old plugs, they have had a pretty tough last few months of winter. Where I have been working it has been basically consistently -30 or below. It doesn't love to start in that with just the oil pan heater, and when I left it unplugged one time it would not start when it was -36, and I really flooded the shit out of it and killed the battery lol. It really had a tough time starting and running following that, the idle surging was crazy and I may have triggered an idle relearn in -36 with a flooded truck. I am hoping this has to do with the amount of soot on the plugs, or maybe that is just how a GDI plug looks after 119,000km and 21 years. The back two plugs on both sides of the engine were pretty scary to remove. They spun out 1/4 turn and bound up, both of them. I sprayed the shit out of them with penetrating lubricant, left if a few minutes, and worked the plugs back and forth until they were smooth as eggs, but it was still nerve racking. The spark plug tubes are very skinny, I will likely order a smaller spark plug socket, but for now I had to make due. The intake manifold wasn't installed true, so there is a small offset on the top side between the spark plug tubes and the intake manifold (where the coil packs mount). I had to grind down this socket to snake it through that, which worked and saved me from removing the intake manifold. Next job was the microfilter on the high pressure fuel pump. What a pain. It was on the back of the engine, and it isn't even listed in service manuals as existing, but some guys have worked it out that this is a potential cause for issues on the GDI engines. Where flash light is pointing, exists this: It is about 6" down the back side of the engine, you have to crawl all over the truck to get to it, and I dented the top of my radiator with my knee during this process. You need to remove those two little bolts (10 mm with the Phillips head) and pull out the fuel line, then take a screw, screw it into the existing filter, and remove that. Followed by tapping the new filter in. This is all happening in a space with next to no room, where anything you drop falls into the abyss. Luckily I ordered two microfilters, and I dropped the first one and couldn't find it anywhere. This little jasper. Also replaced these bits. For whatever reason, missing all that on the fuse box is very common. I also replaced these rusty fasteners on the windshield cowl, they just looked so out of place. I don't know if it was the plugs, or microfilter, or cleaning the throttle body but it seems to idle a whole lot smoother now.