Hi, everyone.

I just bought a '92 Civic LX with a 1.5L, 16 valve engine and a 5 speed manual tranny. It has about 124,000 miles on it, and is in really pretty good shape. It runs very well, but I noticed something a bit strange. I was hoping maybe someone could shed some light on it for me.

When I am sitting at a red light, tranny in neutral and foot on the break, the car idles a tiny bit rough. The strange part is, if I take my foot off the break pedal the engine idle jumps up about 500 rpms or so, for a second or two, then settles back down. I can repeat this as many times as I want by stepping on the break and then letting it up.

Any idea what that's about? I was thinking maybe a vacuum leak going from the throttle body to the break booster, but those hoses seem to be solid. Any help is greatly appreciated!

Thanks!

 

if you pump the brakes the idle rpm should go vary, if you pump faster it should climb up roughly 500 rpms. sounds normal to me.

 

yeah, this is not a ruff idle, this is normal in many cars, i got the same on my legend and i see this on both of my civics. even when i turn the light switch on i see the change in the rpms.

 

Really? Geeze, I don't think I've ever driven a car without power assist breaks, and I've never noticed the idle speed changing when I came off the break pedal. Even in my old '94 Civic.

Wierd.

[:-]