any one know what can cause a 2005 honda odessey ex-l to all of a sudden always on a hill loss power then check engine light flash . some times if you turn vehicle off for a while it would run fine untill next trip or next good hill. take it to dealer they reset computor . say unable to duplicate problem. this has happened 4 times however only three times documented by dealer ship. this started doing this at 9000 miles we only owned van for 6 months now we have 53000 miles but we have extended warranty.it has happened 2 times in 6 months this past year 2008.hope someone can help we are very frustrated we love our van but will not take on a trip due to probblem

This might not help in your case, but I had a similar situation in my '05 Accord V6. I think it happened at around 50-60K miles. I filled up early one morning and headed out on a 270 mile trip. At about mile 255, while going up an incline, my check engine light began flashing and the power from the engine dropped off quite a bit. I had to keep the pedal down almost all the way to the floor to maintain 60 MPH. It was 4am, and there was nowhere on that interstate I felt safe to stop, so I kept going the next 15 miles to my destination. Besides, at that point my engine was running. I was afraid if I let off on the throttle the vehicle might stall out and not restart again. As I pulled into a parking lot and let the car idle, the car was shaking and there was a smell of an overly rich air/fuel mixture. The car was vibrating like it lost a spark plug or two. The whole time, since the problem first started, my check engine light was flashing once per second and never stopped. Even as I sat there idling, roughly. I shut it down and left the car there for about an hour. When I went back out to restart it, it came up just fine. The car started normally and idled fine and the check engine light was out. I drove it about 10 miles to a dealership and it drove just fine. I described exactly what happened, when it happened, and where it happened. They were unable to find a problem. The computer didn't store any codes and the car was running normally. The only solution the service manager could give me was that I may have used cheap fuel and when the car sensed something wrong with the detonation in the cylinders, the vehicle more than likely went into a lower performance setting so that it could be driven to a safe location. Sort of a "limp mode" I suppose. Thinking back, I normally use name brand fuels. But that morning, I had filled up at an old off-brand place. So perhaps he was right: bad fuel.

Do you remember where you filled up last prior to your problems?

There is a similar problem going on with another member on the forum and I think it's the same thing as I told him, as crazy as it sounds it could be your battery. I had the SAME EXACT problem, and I took it in, told me they do that when the battery is bad. Are all the your warning lights coming on?

Hi, I just had the same problem happen to me on a trip. I have not taken it to the dealer yet. What happened in your case?
Thanks - Mike

Hi, I stop by AutoZone and had them check the diag codes, only had a P420 for the Cat Converter. I was surprised there were no other codes. I had them check the battery also, it was good. Any updates to how your situations were resolved would be appreciated.
Thanks

I have a 2000 EX, also have the P420 came on at 30k, 75k and 125k. I found that I have to remove the intake manifold and clear the EGR pipe that Honda installed under the RECALL early on. Also I cleaned the PCV valve too. This usually gives me 45K of peace. Hope this helps.

All three times I had this problem the tempreature was down in or below the 20's. Since it's warmed up, I've not had any issues. I never did take it to the dealer since there were no codes.

I thought we finally had this same exact problem fixed (while driving uphill, complete loss of power, check engine light flashes then stays on)...and then it happened again to my wife today. It's back in the dealer's shop tonight awaiting another evaluation tomorrow. This must be the seventh or eighth time we've taken it back to the dealer with this problem, which started only a couple of months after we bought it new in '06. Last time, they replaced a minor electronic component and it has worked fine for several months. We are really getting frustrated over this problem. Clearly, it is somewhat common so why can't Honda fix this issue?
I've owned four other Honda vehicles since my first one, an '84 CRX, and have always praised and recommended Honda to my friends and family... but I'm losing patience and I'm beginning to doubt their reliability is as good as it used to be.
In July, my 2001 Civic started acting up with similar symptoms and the dealer told me it was "too much end play in the camshaft" and the only way to fix it was to buy a $4000 engine. Seriously? I've always bought Honda cars for reliability. A second mechanic (not a Honda dealer) told me it probably just needed a new sensor. But it would cost me a couple of hundred to have the sensor installed to find out for sure. I'd had enough and jumped ship to Ford. I'm now the happy owner of a new 2010 Fusion. And I love it. Smart, intuitive car.
Hopefully, my Odyssey problem will be solved soon or I'll swear off Hondas for a while until they can improve their quality to what it once was. I am embarrassed to explain to friends that my "reliable Honda" is in the shop once again! Sad, very sad. I planned to drive it to Texas this Thanksgiving but it looks like I can't risk another highway breakdown so the Odyssey will stay home in the garage and the new Ford will get the nod to transport my family safely and reliably to Dallas. I never thought I'd say such a thing!