Questions and Answers

Mazda MX 3 Won't Idle, Idles Too Low Q. Vincent, Hi how are you? Hope all is well. Problem: I could get the car to idle at approx. 800 - 900 rpm's, when I would apply the brake to put the car in gear ( reverse, drive, etc.) the rpm's would decrease to approx. 600 rpm's. When I would come to a stop at a light of sign this again would happen, with the car idling that low it sounded like a washing machine.

Yes all basic maintenance is performed regularly. The car has an Airflow Meter and it is 11 years old. I thought I would check the electrical connections etc. and all was well. When I put it back the first time the car wouldn't start at all so, of course, I must of done something wrong let's do it again. Now the car starts except when you step on the gas pedal the rpm's has a hesitation and then goes to 0 thus stalling the engine.

What have I done wrong in this process? How do I correct it? How do I keep the rpm's at approximately. 800 to 900 when I apply the brake and come to a stop? Thank you for any and all of your help and time.

• 1992 Mazda MX 3
• 1.6 Liter 4 cylinder
• Automatic Transmission
• Fuel Injection
• 120,000 miles

Sincerely,
Marvin

A. Since it was fine before and not fine now, something must have happened with the re-installation. First possibility is that you damaged the Air Flow Meter (AFM). This has a vane type AFM which means there is a vane inside the AFM that is deflected by incoming air. The more air, the greater deflection. There is a potentiometer that measures this deflection and sends a signal to the PCM.

It is fairly easy to damage it. A small dent in the vane housing is enough to keep the vane from moving smoothly and causing idle and driveability problems.

Another, more likely, possibility is that you left one of the air hoses off. There are two air hoses that attach to the Intake Air Duct and leaving either one off will keep the engine from idling. Also make sure the Intake Air Duct is properly and securely attached to the AFM.