My 03 gt 5spd with nitto 555s will throw u in the back seat at WOT after a easy 2 or3 minute warmup to about half way to operating temp. But once it gets hot then it has this lack of accelerating like it stays in lower Rpms for a longer period. It's like it lost 20% power. I have replaced fuel filter, plugs, air filter, cleaned maf. It runs good, no sputter, or cutting out, it just loses acceleration. Also no cel or codes. Could the heat affect it this much? If so, what can help this?