Back in about 2006 I decided I wanted to "do it right" so we went through everything, hoses, new caps, rotors, plug extenders, plugs, wires, careful CO adjustments - everything. And it would still surge with the new O2 sensor. I hated it, it was like I was VERY slightly tapping the brake pedal as I drove. I stopped on the side of the road on the way to work one morning and unplugged it. I made it about a week. Back to smooth as silk again instantly and still is 12 years later. Interestingly it was disconnected when I bought it. Everyone told me to just leave it unplugged, even mechanics that charge to "fix" it said don't bother.