Backfire through tbi

[snowball]

Hi all,

I'm having trouble with my 90 burn tbi. Engine is 1 year old.

Runs fine when I first start it, but as she warms up she starts to backfire through the tbi. Especially on the highway.

I've replaced the plug wires, plugs, cap and rotor. Checked the ignition control module, it was fine but I replaced it and have the old one as a backup. I also set the timing.

Any ideas would be greatly appreciated