Mazda 323 Auto Idling problem
 

Hi all, new on here. I wonder if anyone has experienced a problem similar to mine. In normal idle it is fine, just sits there at just under a thousand revs, but when it is in drive and the car is stationary, the idle is all over the place and the engine stalls. Thanks in advance.

What is the year and engine type you have?
Assuming that your engine is nicely tuned up (plugs wires, airfilter etc) it is most likely an issue with the idle speed control. The ECM should realize that you are in D and should raise the idle speed in response. So look at all electrical connections near the throttle body and also at the transmission. Some times it is enough to disconnect and reconnect the harnesses.
If your engine needs a tune up, well, just do that.

....and check if the air intake hose is cracked. When you put it in gear the engine will tip a little and jank on the air intake hose. Any crack there could open and cause the rough idle and stalling.
If it is cracked use duct tape.

Thank you for reply, the air intake is defo a starting point. It's a 1999 1.8 exec. I'll let you know how I get on.

Mr Tanprotege you are an absolute star. Big split on the underside of the top air inlet hose. Taped it up for now, and runs like a different car. Many thanks and a very happy new year to you.