It won't hurt to change the filter,
it's not hard to do and they don't
cost much, but it's a guess, did
you check the timing ? that's a
factor too, glowing red can be from
too much fuel too, I've seen a cat
glowing from under a car from raw
gas getting to it, could be you got
a dead rat in the muffler too.....
ya just never know, I once worked
on a Corvette that a stupid rat packed
the muffler full of dog food.... so go
figure, check all the factors, use a mixture
meter on the exhaust, might have a bad
O2 sensor.............