I was having the same problem with my 60 just recently and I took it to a mechanic to trouble shoot. He checked everything I did an found nothing. But when he removed the carb he found the problem. I had a cracked intake manifold, a common problem from what I understand. If all else fails, check...
I have three vehicles and one has to go. I really like the old rig, but I think that want a newer more comfortable riding rig....like a FJZ80. I have had some good time in the thing, but it is time to move on. The rack comes with the rig and only 2 lights because some a$$clown stole the other 2...
I regret to have to sell my rig, but I just don't have time to enjoy it. Asking $6,000 or offer. You can also look at my profile for more pictures and a video of it in action.
Wow, does your 60 have fuel injection or is the gas mileage increase because of the H55? I have measly 31's on my 60 and I only get about 11 MPG with a tailwind.