Why is the "Check Engine" light sometimes on?

"The check engine light can mean a variety of things. If it is not blinking it is typically related to the Emission Control Systems.

Take the car to an AutoZone, PepBoys, or any of the auto parts houses. They can plug the reader in and pull the code.

Typically it will mean;

- Gas Cap Loose

- O2 Sensors (Oxygen Sensor to determine how rich or lean the air fuel mixture is and whether the Catalytic Converter is doing it's job)

- MAS/MAF Sensor.

Anything can trigger it, it's best to have the code pulled and you can easily determine what the system is complaining about."

"tighten down your gas cap .check Eng. light is emissions.""smog related""

watch and see if it comes on after fueling . about 10 min. down the rode ."

"There is a very common problem with the Corolla that causes this.

It is a dirty MAF (MassAirflowSensor) and it can easily be cleaned.

There are several guides on the web, Google ""Toyota corolla maf sensor"". Expensive electronics cleaner is not needed, Isopropyl alchohol and a Q-tip will work fine.

You will need a scanner to reset the EngineCheckLight (Autozone or a friend) or I think it will automatically reset after about 40 times you start the car?

This is a 10minute repair. For some reason most professional mechanics do not know how to Google!"

valve seats needs to be replaced because when it's cold the rubber valve seats let's the only down inside the cylinder head once it warms up the rubber valve seats keeps it from smoking you need to get the valve seats replaced

"as regards fuel issue.

your fuel pump in the tank could be failing. never run the tank to the bottom. i've heatd of leakining injectors on these models. but right now i'm rebuiling a 2002 1.8 lit., corolla. cusomer just smoked it at 160,000. if the head was bad thats $390.00. if the engine core is unrebuildable than a used, 90 day garut., engine is no less than $1,100 , and then it's still a used engine. plkese rebuild your top -end at around 100,000 miles and rebalance. timing belts on time, and note to you mech. the tensioners fail prematurely,. go to 30,000 replase, not 60,000. and completely rotate out trans. fluid at 70,000 or more. some manufact. specs are wrong , torques wrong, factory quality contrl issues . go with your gut and still aplly old school rebuild ways.. we havn't had a rebuil return in 5 years.. Kraig"