Posted by Cliff Robb on September 09, 1998 at 11:04:39:
Ok, so I'm playing around with the idle speed screw on the throttle body last night. I like it to idle just a tick under 1000 rpm, & it seems like I need to tweek it a little every few weeks. I am reasonably sure I have no vacuum leaks, and the car does idle smoothly. A couple questions: Someone recently mentioned if the idle speed increases or decreases when you pump the brake pedal, the mixture may be rich or lean. I quickly scanned the postings & could not find the topic. Could whoever posted it kindly tell me again? Also, my car idles smooth, but over the last few months, I have noticed it hunting up & down about 50 rpm like the O2 sensor is making corrections. I thought the O2 sensor was out of the loop at idle, what gives? If I unplug the sensor-rock steady idle. Maybe the mixture is off. as I said, it speeds up when I pump the brake. On the mixture srew on the AFM, do you tighten to lean & loosen to richen? I was thinking of experimenting a little, making note of the original setting. So let's hear it, what do you all think?