2005 Accord 4 cyl High RPM Dashboard Air Sound

[cogitofire]

My 05 Accord 4 cylinder is having some issues. For a while now I have heard an odd sound from inside the vehicle. It sounds a bit like a vacuum leak during acceleration but when I pop the hood and listen for it, there is no sound. I have checked all vacuum lines that I can find and I cannot find any issues.

Just went on a 200 mile drive and while on the highway I have a new problem. When I am accelerating from say 50-60 mph up to 65 or 70, I am getting a bad noise and a surging problem.

The sound is coming from the dashboard about where the defroster vents are. The sound is of rushing air and it is loud enough that it sounds like the defroster is on. The engine surges or lunges a bit and it feels like it is starved for air/power. It also does not want to go shift gears but it primarily happens at about 58-59 mph and when gunning it, my vehicle does not usually shift until I hit about 60 mph

I do not feel like a little vacuum line could create that much noise if there was a crack or a loose hose. If it was some sort of intake problem, I figure that the mass air flow sensor would recognize that bad of a leak. PCV valve seems fine and is not overly dirty.

I am at a loss of what to do. Being short on cash right now, I would like to fix the problem myself. Have any of you heard of this type of issue before?

[cogitofire]

After driving around the block a bit I determined that the hissing vacuum type sound I was hearing was coming out of the exhaust. It was not under the hood and not in the dash. My father in law thinks that it is a catalytic converter problem, perhaps a clogged cat. We think that the dashboard sound may be from back pressure when at high RPM's. I left Austin headed for Dallas and everything was working fine just making a bit of the hissing sound. I got to Hillsborough and I suddenly started to seriously loose power when accelerating. After exiting and slowing down I heard a bad rumble under the rear of the car and thats when I called it.

I went ahead and called for a tow to Dallas and dropped it at the dealer. After unloading it I drove into a parking spot and could tell that I had almost no power at all.

On a good note, after I fiddled with the car all weekend long, my mother in law walked up and asked me why I didn't just take it to the dealer. I told her I was trying to save money and she then told me that she must have forgotten to tell me that they had purchased the 100,000 mile extended warranty. Yay for that!

On a side note, the Honda roadside assistance is crap. They tried to send a tow truck from Corsicana which was about an hour away who also wanted almost $6 / mile. Honda covers the first $100 with our extended warranty and I was going to be $200 out of pocket. I called back and told them how stupid that was and they said I can get who ever I want to tow the car and get reimbursed later. I found a guy about 2 miles away who towed it for $3.50 / mile. $220 total and I get $100 back.

[cogitofire]

Well I have resolved the issue with my Honda. I suspect that this is not a common occurrence but I will post it just in case someone else on the forums ends up with the same issue.

The problem ended up being the resonator which is the small muffler looking thing that is between the catalytic converter and the muffler. It is a sound dampening device that is filled with baffles. It appears that the weld broke that was holding on the rear baffle inside of the resonator. The baffle eventually found its way to the very back of the resonator and wedged itself to almost completely clog the exhaust.

The dealer wanted to replace everything from the cat back which would have been $600 because it was not covered by my Honda Care extended warranty. I found the closest muffler shop to the dealer and drove it over there only able to go about 10 mph. Once there, the mechanic cut the muffler off and found that it was not clogged. Then he cut the resonator off and blew some air through it finding that it was clogged. His curiosity got the better of him and he cut open the resonator to see what had happened. He said that he had never seen anything like that before and that he did not know why it would happen.

Fortunately, I do think I know what happened. Two years ago, my wife was behind a semi truck that threw a tire and she could not avoid it. It damaged her hood and rolled under the vehicle, denting the original muffler. The truck's insurance covered repairs and we had a new OEM muffler put on. I suspect that the resonator took a hit during this incident that started the chain of events leading to the clogged exhaust.

The moral of my story is that you should always pay attention to odd sounds even when everyone else tells you that it isn't there.

$220 Tow, $39.99 Honda diagnosis, $108 new resonator. Total cost = $367.99 and I am hoping to be reimbursed $100 from Honda Care for the tow.