OK let’s get the particulars out of the way: I’m a member of three off-road clubs here in southern Nevada and sometimes I go with the other ones too, a lot of mountain trails, so high altitude. Hot as hell during the summertime. Usually when the club stops on the trail either for a Pee break, lunch break, snack break or somebody snaps their axle/ engine problems or gets stuck, I jump out and immediately unscrew the gas cap and relieve the pressure. And this has been happening over the years, it’s nothing new and yes I’ve read many write ups about it on the various 100 boards. So far I’ve replaced the fuel filter, I put heat shielding around the fuel lines where they passed by the cats. It was suggested to me by another club member that the 100 has a breather valve and sometimes they get stuck. Where in the hell is it? I also had another friend suggest that maybe the catalytic converters are clogged, I wouldn’t doubt that since my rig is 26 years old now. I’ve gotten underneath it many of times and there’s no fuel leakage. There’s no fumes in the engine compartment, it’s all towards the rear. 2 years ago I drilled a hole in my fuel cap so it would relieve the pressure. I know this is a very common problem, but nobody seems to have an answer on how to fix it……. So what’s the latest opinions on it?…. see you on the trails.
