91 740 b230ft. Hey all! Lately I've been noticing at the stop lights my idle hovers between 650 and 750 rpms. Is this a problem? I cleaned the throttle body and replaced the knock sensor and coolant temp sensor last month. And just replaced the water pump (bearings were shot and was affecting the idle). I also checked for vacuum leaks and found none. Thanks!

 

warm up car, shut off all accessories (AC, headlights, stereo, etc), idle in neutral, note speed its idling at, put in drive with foot firmly on brake, idle speed should remain relatively constant although it might dip for an instant

headlights on, A/C on, and it STILL should be fairly constant.

common sources of erratic idle are air leaks in intake path, a gummed up idle air controller, or a gummed up throttle body. also, a system that had one or more of those symptoms that someone has tried to 'fix' by hacking on without curing the actual problem.

if so, then your idle is working well enough.