I have a 98 tacoma 5 speed 3.4L limited 270K miles and the past few months at 3500 rpm stationary or in gear it sputters and backfires. Checked and cleaned plugs, cleaned MAFS, removed cat and ran it, cleaned fuel filter, new gas, cleaned throttle body, and PCV. Still running the same way. No CEL but every now and again the check engine light will come on and when I try to pull the codes it will do nothing and then i turn it off and back on then the CEL is gone. So random. And MPG went down hill I believe as well. Have been searching for ever it feels like to find a solution and have heard some people fixing it by different ways. But the cards don't seem to be in my favor on this one!