So Im new to civics, got one a week ago and only have 1 concern. I did a search and couldnt come up with the exact answer so I'd appreciate a bit of help. The car is a 97DX with 100k miles.

Whenever the car is idling about 75% of the time it idles smooth but when i bring the revs up and let them drop down it gets rough for a few seconds then it comes back up to normal idling. If im stuck in traffic the engine idles rough and i feel vibrations in the car but then always goes back to normal and then rough sometimes again.

 

Also when accelerating or decelerating I feel like the car has no problems and the car has no Engine check light so im figuring this is a small easy fix just looking to get it out of the way.

 

One more thing I noticed is that when it is idling it idles at 1000 rpm and drops to about 850-900 then jumps back up again so Im pretty sure that should help pinpoint the problem. I installed an autogage tachometer i thought it was the tachometer but I dont think it is now after reading that other people also idle at 1000...

 

few simple things i'd check or do are
clean the fuel injectors - fuel additive
distributor - cap, rotor
spark plugs, plug wires
timing - belts, TDC marks


Modified by 94sohcVTEC at 4:10 PM 7/1/2005

 

Check for vacuum leaks.

 

mine did the same thing....the timing was off a tooth..by the way search there are 100's of threads about this

 

I'm with vacuum leaks on this one.

 

This may seem kind of obvious possiblity, but check the idle control valve.