Mechanics

WHY CAN'T L MAINTAIN PROPER RPM OF 850-1000 WHEN THE A/C NOT RUNNING?

1999 Honda Torneo • 85,000 miles

L have to increase my idle on a daily basis, or keep the A/C on to prevent the engine from shutting off. With the A/C off the car will cold start fine and idle just above 1000rpm. Once it has warmed up, the idle goes below 500rpm and engine dies if l shift into reverse or don't press on the gas. When in drive, l must shift into neutral to make stops as l have to keep pressing on the gas or the engine will shut off.

With A/C on, rpm fluctuates between 850-1000; driving and stopping is normal however, when reverse gear is selected, the rpm goes below 850 but not too low to where the engine will die. L have replaced the air filter and removed and cleaned the throttle body but the problem won't go away,

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Xyzlead
October 3, 2012.



First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

Wrenchtech
Oct 3, 2012.
Have the valve clearance checked as well. Improper valve clearance can cause erratic idling.

KHLow2008
Oct 3, 2012.