Mazda 121 Soho: Irregular Idling, switching off often. Sometimes lack

@thennow the most common reasons for that are

• Air/Fuel mixture too lean
• Air leakage
• Fuel injection control malfunction
• Low fuel line pressure
• Low Intake air amount
• Incorrect idle speed
• ldle speed misadjustment
• One or more spark plugs not firing
• Low engine compression
• Carbon deposit in injection body

Your brief description of issue would lead me to check the fuel supply. I am sure you have already checked your plugs to see if you are burning rich or lean. If not, do it. Remove the spark plug and look at the face. If it is oily etc. your engine might have worn rings, bad valves etc. If it looks really dry and burned with a white-spotted look it is because of your fuel mixture being to lean.

Check your fuel filter, your fuel pump and measure the fuel pressure. Make sure that your fuel injectors are functioning properly and are clean.Your engine may just not get enough fuel. To help you further, we need to know the exact model year and engine size.