Idle

Hi guys
when a/c unit ON idle very bad -any clue
Thanks
George ,Baltimore 

What year and model is your Mazda MD. If the idle up system is operating normally when you create a large electrical load such as headlights, heater fan, and rear defrost or when power steering is turned to full lock then sounds like the A/C compressor could be siezing up and dragging down the motor.

Hi, Thanks for respond
Mazda Protege 1998  DX 1.5 L 92 HP
Any load : Idle just fine  - BUT if  a/c ON - engine getting funny -about 300 RPM up and down ,- I thought EGR Valve
Regards,George
 
 

Hi
One more thing - Voltage regulator OK
                            Ice Cold Air/ Hot Air OK
                            Battery OK
                           a/c Unit Running just Fine -nice and quite
                           ****
my thoughts - EGR or Amps/like short circuit/
Thanks 

EGR could be sticking open and little at idle as you note. Also could have an idle air control valve getting weak and just not able to compensate for that large of a load.

Thanks