I recently bought a '00 SSEi with 65,000 miles. While driving home from the dealership, I experienced the surging problem several other people have described. I initially suspected the trans and changed the fluid and filter with no improvement. After some research, I decided to change my stock spark plugs to NGK TR55s and replaced the wires with Delcos. At the same time, I also cleaned the cables as instructed throughout this forum. At first the problem seemed to be gone but came back within a couple of days. Shortly after, I also found that the transmission was shifting very hard after sitting at idle in traffic for extended periods of time. I began to suspect the trans again and after more research found that the pressure control solenoid and/or TCC valve could be causing my problems. Sonnax has produced a "sure cure kit" for the 4t65-e. According to the company, this kit addresses all known deficiencies for this transmission - including the PCS and TCC valve. While searching for more information, I stumbled across the instruction manual for their kit in PDF format. On page 2, I found this in the tech tips:
"Fluctuating RPM with TCC applied can be eliminated by cleaning the Mass Air Flow Sensor and disconnecting computer for several hours to clear memory".
After finding this, I decided to give it a try. I bought of can of MAF cleaner, disconnected the battery - again cleaning the cables - and cleaned the MAF according the directions on the can. While I was under the hood, I also checked the resistance on the coil packs, cleaned the terminals that connect to the primary windings (which were not that dirty), and applied a small amount of dielectric grease to each one. After leaving the cables disconnected overnight, I reconnected them and drove the car expecting no change. Instead, almost a month and 3,000 miles later, the problems have not returned.