We have a 2007 Honda Odyssey
, with a VTEC engine. A little over a year ago, the Check Engine light came on. When this happened, the engine lost power. It sputtered. It had not acceleration at higher RPMs, just prior to shifting. The error codes indicated that the number six cylinder misfired. The dealership replaced the plugs. It ran fine for a year. About six weeks ago, it happened again. The Check Engine light came on. The engine lost power and started sputtering at higher RPMs. It would hard shift. This time, the number one cylinder misfired. There was also a battery charge system malfunction, which is probably not relevant. The dealership could not diagnose the problem, but wanted to change the fuel injector, but could not guarantee that it would fix the problem. We got a second opinion from an independent service center, which replaced the EGR valve. It ran fine for about a week. When we tried to tow an empty trailer, it happened again, about two miles from our point of origin. We took it to another independent service center, which specializes in Hondas. They had it for two days. They examined the valve train and could not diagnose the problem. The engine appeared to be running fine, so they returned it to us. About a week later, it happened again. It intermittently happens, on random occasions, with no apparent trigger or reason why. It can happen immediately when started, shortly after being started, after driving a period of time, or may not happen for days. It can happen when sitting still, or while driving, regardless of the speed. It can happen when it is nice out or in inclement weather. The engine does not seem run as smoothly as it used to, even when the check engine light is off. At the onset, just prior to the Check Engine light coming on, you can feel an erratic operation of the engine, then the Check Engine light starts flashing, then you have lost power, the engine has no acceleration, and begins to sputter at higher RPMs. During these periods when we encounter this problem, our gas mileage is reduced, significantly. I should add that the Check Engine light also flashes when we encounter these problems. I have notice, that on a rare occasion, when we feel the engine begin to operate erratically, if we accelerate, the check engine light goes off, and the engine appears to run smoothly. On a few occasions, we raced the engine in neutral, and the Check Engine stayed on, it ordinarily flashes, and the engine appeared to run fine. Some times when can turn the engine off, and turn it right back on, and the problem is resolved. Sometimes the vehicle can sit in the driven overnight, and the problem resolves. We recently checked the error codes, and now the one, four and six cylinders misfire. We also found and error code indicating that the barometric pressure sensor has malfunctioned, and that the ECM PCM has malfunctioned. The vehicle has about 150K miles. American Honda says that all we can do is take to a service center. We have ruled out plugs, coil packs, and fuel injectors. No one can figure this out, and it is becoming a costly endeavor. We are thinking about changing the barometric pressure sensor, to see what that does, or maybe the gas cap, to see if that has any effect.