In TFTM Blurr just disappears after Hot Rod et al arrive on Junkion.
During the battle with Unicron, you see Kup, Arcee, Springer & Daniel in the Quint ship, you see Perceptor and Ultra Magnus' arm in the Junkion ship, and the Dinobots somehow got there, but Blurr is nowhere to be seen until the end ofthe movie, when Rodimus makes his speech about the "end of the Cybertronian War".
So, where'd he go? I suspect that he was on the Junkion ship with Magnus and Perceptor, but I have no proof of that. I've got just as much proof that he rode a bicycle back to Cybertron.
Anybody have anymore info on this? Didja spot Blurr at all during the fight with Unicron? Where was he hiding?