My 93 civic dx has a kind of rough sound, it sounds like a subtle and more high pitched sound of a diesel engine, like that kind of low vibrating, percolating sound rather than a nice hum like it should (I know, cheezy desciption but its hard to explain).

Its pretty consistent all the time, and doesn't change much in frequency despite my mysterious flucuating idle. It also seems to have gotten worse over time. I did notice that it got more intensified after I did a valve adjustment.

It it the sound of a bad valve adjustment? Thanks

 

i think i know the sound you are talking about. i hear this on some of the mid-new toyota corolla and thought its just the car but then i herd it on my friend's car too. we did some research and it was related to the throttle body. the air coming in made that noise. try adjusting your throttle or intake or around there. maybe that'll help. hope this help. good luck. it work for my friend's.

 

piston slap, rod knock??? valve lash???

 

Yeah actually after reading up a little bit I bet its the valve lash. I think I loosened them up too much and they are noisy now.

 

you loosened your valve adjustment??? why, they dont tighten on their own, no need to ever loosen them.

 

What? Yeah they do. They get more tightly pushed into the rocker arm over time.

 

are you serious???? no they dont.