Hi guys- My '99 Honda Accord (auto, 4-cylinder) has been louder then normal ever since l recently bought it. The car gets abnormally louder as it gets faster. At 25 mph, it is a slight hum. By 50 mph, it is an unbearable grinding sound! The car is also very unresponsive- l need to push the gas pedal down very far to even accelerate at a reasonable rate. The car also jerks every time it switches gear. HELP PLEASE!

PS. The jerking/unresponsiveness problem is related to the noise (proven- l shut off ignition with the car running at 40+ mph and noise was still present). My guess is that it is coming from the axle/bearing, but could not be fully sure. l should also add that l have loose/broken motor mounts, which l found out could be the root of both problems, after l did much research online regarding my problems. As for transmission fluid, it is in need of changing(it is dark brown!). I am thinking of getting a transmission fluid flush today. Please tell me if getting this flush would be worth it. Thanks mucho!

if the noise increases with vehicle speed then u need to look at the rotating items. Cupped tires will cause the noise as will a bad wheel bearing.

if the noise is proportionate to engine speed then look to a restricted catalytic converter.

the lack of responsiveness can be caused by a restricted catalytic converter which would be consistent with the noise. try putting the car in neutral at 50 miles per hour & let the engine speed drop to idle. if the noise goes away the problem is with the engine. if the noise remains its with the tires or wheel bearing.

to isolate a tire noise, start with rotating the tires. if a tire is cupped moving it from the back to the front will usually mute the noise. A cupped tire looks like it has scalloped edges or like ur palm does when u turn it upward & form a cup with that patter repeating around the tire. if the noise does not change with a tire rotation then its a wheel bearing.

if u have a wheel bearing noise & a non-responsive throttle then have the throttle body cleaned out. the lack of responsiveness is usually due to carbon build up on the throttle body & throttle plates that cause them to stick. carbon build up is like soot in a chimney--it gets sticky & makes it feel like ur pressing down on a brick when you're trying to accelerate. regular spray throttle body cleaner or carburetor cleaner is usually enough to fix that problem.

the hard shifts could be related to the throttle body or motor mounts

hope that helps