Ever since I bought my Civic for the winter, the idle has been shaky. When sitting at a light for example, the idle goes from 1000rpm to 1500rpm, and back to 1000 again. It constantly does this. My dad noticed that it smells like the car is running rich, and my gas mileage has also gone down. What could be the possible cause?

Thanks in advance

 

ttt

 

Is it always like this, or is it intermitant? Possible causes, TPS voltage too high, Map sensor, vacuum leak, IACV.... if the vehicle is at normal temp, if cold FITV.

 

It does it when its warmed up. Anytime I'm not moving, it has a shaky idle.

 

i have the same exact problem...is there a real loud hissing sound from your IM? does your idle dip when you turn anything on (high beams, derfroster, etc)? i had mine working "ok" for a while, but i couldnt stand my idle being soo high...i had to turn on my heater to full blast, headlights, and defroster just to get my idle to about 700...if everyhting is turned off, the car idles at like 1K+ due to me adjusting the screw...anyone have a positive answer to this idle problem? TIA