almost a year ago my 08 accord started to make an odd growling/angry vibrating noise sounding as if it came from under the engine only with accelerating. i have taken it to several dealers and local shops to see if anyone could figure it out, it stumped them just as bad as me. i ended up removing the rain guard and topped it off with oil one night (it did it right after an oil change too so its not from low oil) and the noise stopped for about a good 3 or 4 months. it came back about a week ago. any ideas of to what is making the noise?

it makes the noise only while accelerating and through all gears.

 

have you checked for a loose or leaking intake?

 

cracked exhaust mani, or leaking exhaust im guessing. or maybe some vac line came off

 

exhaust leaks tend to sound like ticks... not growls.
in addition, that is a cast manifold if we're talking about the v6.

 

i have not checked the intake. but it regularly gets serviced at a honda dealership and they woulda spotted a leak. thought about trading it in a little while ago and one dealer we went to thought there might of been an exhaust leak somewhere but an exhaust leak would be more of a constant and this growl comes and goes. no its sadly only a 4 cylinder.

 

post a video