I have had a tapping/nocking noise on the M1009 I used to have. It got progressively worse over a couple minute period, and then I just stopped it and had it towed. Long story short, the rod that the rockers rock on is held in by a bolt at each end. Mine was loose on one end, and caused noise, smoke, low compression, etc. Tightend the bolt, and life was good. I also had all 8 of my glowplugs swell. You can't pull them out with the swollen heads. Some people break them off, and try to blow the head out with compressed air. Here's how I did it, effective but risky. Pull the injectors on affected cylinders out. Pull the glowplug as far out as you can, until it hits the swollen part. Take a pair of pliers and break off the threaded/connector part. Take a new glowplug, and push the swollen part into the head, until you can see it thru the injector hole. If you push it too far, you are probably going to have to pull the head...so be careful. Once you see it thru the injector hole, take a pair of medical forceps, and clamp onto the bugger, and pull it out. I did this on all 8 of mine without much issue. Replace them with AC 60G's, only way to go. I hooked one up to a 12v battery, and let it sit for a few minutes, no swelling. Good luck.