I posted this a few months ago. It still does it. Not always. Maybe 3 out of 5 times I cruise down the highway. If I lock it manually with my toggle switch. It stays in fine. Everyone said it was a ground problem. I'm now out of ideas. My Direct Scan shows it cycling like crazy also. I've tried most everything related to locking the converter....I cleaned the three ground wires linking the computer to the back of the motor, I added grounds inside the car to those same wires. I added engine to chassis grounds, cleaned the battery to engine ground, added body to engine and body to frame grounds. I replaced the MAP sensor, T/P sensor, MAF sensor, And Vehicle Speed sensor. About the only one left is the coolant temp sensor! I've even change the computer. I wish I had another chip to try. Although, I wouldn't think it would be intemittent because of the chip. I'm out of ideas. Any suggestions would be appreciated. If you need more info, let me know. All of this started after the first engine rebuild and installation. Dave C.