Hey everyone. I've got a question about my 2000 Zetec's performance. When driving at a constant speed the engine sometimes (usually) surges as though it can't quite decide exactly what throttle position it's in. When accelerating under full throttle it is very peaky, meaning it pulls harder then seems sluggish then pulls hard again as it climbs through the rpm range. It's got relatively few and basic mods including aftermarket induction, cat-back performance exhaust, and underdrive crank pulley. Stock throttle body, cams, and exhaust manifold. Anyone else have a similar experience? Any ideas/suggestions? Thanks!