We have a 97 Civic LX with 89,9K miles on it. The car runs wells for the most part. The engine has had a metal rattling noise for a while now but it only comes when the car gets a little low on oil (like a 1/2 quart low) and is only heard while driving in the 1500-2000 rpm range. Now we have gotten a new chattering like noise while driving. While accelerating the car will bog down make this loud chattering noise and the car will shake violently. Instinct for me is to take my foot off the gas , I let it coast then hit the gas and the car is fine. The trans shifts fine 95% of the time, the engine runs smooth, with no missing or rough idle. I'm unsure what's going on. I'm not sure if i should be looking into an engine repair or a trans repair, but something is not right! Any insight would be great!

hey man , does the noise go away when the car is staionary
or when you press the clutch pedal ?

Yeah the noises go away while the car is stationary. I can't even duplicate the rattling noise while the car is in park or neutral. They both only happen while the car is in gear. The car is also an automatic so no clutch pedal.

Here's some more information in regards to the noises I am hearing and feeling.

The rattling noise I hear it anywhere from 1500-3500 RPM, again mostly when the oil is getting just a little low...so at the current moment it barely happens since the oil was changed very recently. The noise I hear from this is strictly coming from the right side of the engine. (timing belt area) Someone told me previously that the valve clearance may need adjusting If that's the case how would i go about this?

The chattering noise with vibration. I have figured out it happens around 40mph mostly and if you are trying to maintain that speed specific. However at 20mph and TRYING to maintain that speed , the car makes lots of metal clanking and chattering noises ( sounds like its coming from the bottom of the car)... as well as it acts likes it wants to shutter and shake but it never fully does it. Highway speeds the car drives fine as well as every other speed range. In case someone asks about shifting. The car shifts fine through all 4 gears. Every once in a while it downshifts funny like it'll goes from 4th then feel like it shifted all the way to 1st (car bucks then revs high) instead of engaging the clutch and selecting the gear that is needed. The only other thing is again every once in a while you feel the car shifting into what I would assume is overdrive. Both shifting issues rarely happen on a regular basis.