Question: I drive a 1998 Toyota Corolla 1,6 RSi. Recently, the check-engine lamp has stayed on. When I start the car when the engine is cold, it idles and then shuts off after a few seconds. This would happen a few times and then it would start idling, albeit at a very low idle speed (500 to 700 r/min; usually 1 200 to 1 600 r/min when cold). During this time, any throttle input would drop the revs and even shut off the engine. Once the engine has warmed up a bit, though, it pulls cleanly and without any trouble. When I start it when warm, there are no problems except that it now idles between 1 300 to 1 500 r/min instead of the usual 900 r/min.
MJ NZAPHEZA, Bloemfontein
Answer: In a case like this, we would normally advise you to inspect the air-intake system for leaks (for example, the vacuum hoses), clean the throttle body and check the idling valve. However, due to the fact that the engine-check lamp is on, a failure of a component or system linked to the increase in emissions of the vehicle (see Onboard diagnostics, April 2012) is more likely. Therefore, a code will be stored in the engine-control unit’s (ECU) memory that points towards the failure. Our guess is it’s the mass-airflow (MAF) sensor, which a check of the code stored in the ECU would confirm.
