so coming home from the track my car starts acting up.

at part throttle, like keeping pace at highway speed, it just stumbles a lot, all jerky and bleh.
so i get home, adjust the tps, it was .6 at idle instead of 1.
okay that should fix it, right? wrong. still stumbles, if anything worse.

stumbling goes away when im engine braking or giving it more then part throttle.

what could be causing this?

 

I was experiencing this same thing on the interstate today, I too would like to know what could cause this.

 

do you still have the stock cats and if so, how many miles are on them. my car did the same thing and that fixed it by just removing them (South Carolina). lol. but i would check that, cleaning the plugs up should be another thing.

 

its got a cat, but if the exhaust wasnt all welded together i'd gut it. plugs are old, i got some new ones to see if itll help.

 

replaced the afm

no change

replaced the plugs
replaced the walbro with a stock na pump

made it worse

changed fuel filter
slightly better, but still there.

im running out of ideas.