I was thinking that too, Possible bad injector? Plug ,wires and distributor cap were replaced a couple of years back and we don't put a lot of miles on it.
After engine cycles a couple of times for oil pressure and initially fires I get a loud pop. Had a 0420 code and replaced O2 sensors. I haven't had the code for several hundred miles. Thinking something something is up with the Cats, They are...
Thanks Guys, I run a Walker on my LX 450 and am really pleased with it. Did not know thy made a smaller one suitable for the 40.
'll check out the Walker, that works for me.