Hi, there.

I have an exhaust question that I hope someone here can chime in on. What has happened to an exhaust manifold that when cruising on the highway at around 60, you let completely off the power... you feel vibrations and hear a rumbling noise as the RPMs wind down? Similar thing when stepping (somewhat) hard on the gas pedal - affecting acceleration.

This is on a '94 Accord DX with about 140/150K.

I saw a mechanic today. I went in there thinking it was the catalytic converter, but he said it's not. So, I'm assuming it's the exhaust manifold. My exhaust pipe has been replaced recently from the catalytic converter on to the muffler. I thought that maybe them replacing it, and using pneumatic tools (and whatever else) has cause some sort of shift.

I think my situation closely resembles the one posted on here and the response by carlos38
http://www.automotivehelper.com/topic145485.htm

Thanks much.

 

I would look for exhaust leaks at the gasket locations; fore and aft of converter. Also remove exhaust manifold heat shield and look for a cracked exhaust manifold, or leaking exhaust manifold gasket. You can usually see evidence of hot exhaust gases leaking.

good luck

 

Do any of the issues you mention require immediate attention? Or, can I drive on them for a while? (I'm moving soon, that's why I ask).

Thanks.

 

So, just got back from looking at my car. Unbolted the heat shield, but couldn't take it off completely because of the radiator hoses. As far as I could tell from what I was able to visually inspect, and smell (after turning the engine on), the exhaust manifold is ok - no cracks.

Still think the problem comes from somewhere between the catalytic converter and exhaust manifold. But, then again, I could be completely off.

Any thoughts?

Thank you.

 

When you're on the gas, or when you're engine braking, the engine rocks back & forth in the engine mounts. If the mounts are too soft, or broken, then the engine rocks TOO far. That moves the exhaust system up & down, also moves fore & aft. Maybe the exhaust pipe is simply hitting something, like the heatshields bolted to the underside of the floor-pan.

If you can inspect it well enough to convince yourself that the exhaust isn't actually leaking, then you can be a little more laid back about fixing it immediately. Better yet, if you can find evidence of WHERE it hits, then make the judgement.