idle problems

[rone_305]

my car has been idling at 500rpms when the a/c is on i have the check light on: P0401 Insufficient EGR..... most a/c will accel when it comes on but my doesnt......NEED TO FIX THIS PROBLEM

[toyomoho]

P401 Exhaust gas recalculation flow insufficient detected.

The engine is not getting enough recycled gas from the EGR system. Causes could be stuck closed EGR valve, defective EGR VSV, MAF or MAP sensor, and EGR vacuum hose leaks. The actually EGR valve or the gas tube running to it may be plugged with carbon up, they can be removed and cleaned.

The EGR should be off at idle and not contribute to the A/C problem unless stuck open. In this case the basic engine idle should also be poor.

The problem with the A/C engine idle could be the A/C amplifier or bad wiring.

How is basic engine idle, OK? Is it higher when the engine is first cold started? How does the idle respond when dropping into gear, if the engine idles OK and does not when in gear the IAC valve should be OK.

[rone_305]

well when the engine is cold it wont accel it idle's low and yes i hear a vaccum leak but i just cant find it..

[Gadgetjq]

Originally Posted by rone_305

well when the engine is cold it wont accel it idle's low and yes i hear a vaccum leak but i just cant find it..

Try this old 'shade tree mechanics' trick. With the engine running, spray carb cleaner around the area you 'suspect' the leak might be. When the cleaner is drawn into the intake by the leak you'll notice a change in the idle. You should be able to zero in on the problem with a few more sprays.

Cheers