Funny, mine always runs slower and a bit rougher with the ESC wire unplugged!

My old post referred to attaching the large bundle of ECM ground wires. On the 2.8 block, there's a specific place for the wires to bolt to. On the 3.4 the bolt hole is not present, but the crank sensor does go in the side of the block at approx the same place. So, after scratching my head for a while I decided that the bolt holding in the sensor would do just fine as a grounding point! Works great.

Note that if this doesn't sound familiar to you, there may be, laying loose somewhere in the pssgr side, a big bundle of wires all ending in one large "ring" or "lug" which must be grounded directly to the engine. If this bundle of wires isn't grounded, it messes up all kinds of stuff with the computer. And if I recall, may also serve as a ground point for the ESC system.

On the knock sensor, the 3.4 had one in the forward, upper side of the pssgr block. The 2.8's sensor was located aft, and lower down. Both holes are present on the 3.4, the one not used is plugged. I just moved the sensor to the aft lower hole and plugged the former sensor location with the plug removed from the aft hole.

At any rate, the difference between the ECM ground bundle and the single wire that plugs into the knock sensor should be obvious. If that wire bundle isn't grounded, it could explain your engine's strange behavior.

Maybe a fishing expedition is in order!