Check engine light on 2000legacy comes on after a few miles and stays on until engine is stopped. Re start engine,no light again until afew more miles.

SOURCE: 2001 Subaru Legacy Engine Check Light

I had the same problem, and the reason was the sensors, will need to change the catalytic sensors some vehicle have two, they called front and back, get under the car and locate them, they have a electrical plug and are easy to remove, is like removing a spark plug but some require a special socket I hope this help

SOURCE: Check engine light and intermittent bucking

You might get lucky here. Go out and open the hood and start the engine when it's dark. See if you can see sparks jumping around the spark plug wires. That will tell you for sure. Otherwise, my first choice would be to put on new plug wires of the highest quality you can find. I've seen this type of problem before, and it can be made worse if the boots on the wires are not clean or too much grease was used at the factory. The solution was to clean everything and replace the wires and spark plugs because carbon tracks have been created that can't be easily (if at all) cleaned from the spark plug insulators. The coil towers will probably be okay if you clean them well.

SOURCE: check engine lightp0170 fuel trim bank one check

I'm guessing your mixture is too lean and it's possibly running a bit rough and there isn't enough fuel getting to the engine. A rich mixture is too much fuel, but that error is usually related to O2 sensors. It might be the O2, but 'trim malfunction,' you're looking at a vacuum leak. Check the oil separator valve then the throttle body gasket and then the intakes. Most likely a vacuum leak and the throttle body, oil separator and intake are the most likely. Run your hand around the bottom of the throttle body and oil separator, if it's greasy/oily there, there's a leak.

If there is no leak, test the MAF sensors...they might need cleaning, and in a worst case scenario, might need replacing.

Stephen

• 21873 Answers
• Posted on Sep 17, 2012

SOURCE: engine not hot temperture red lines ac and heat stop until the hand come back down

Could be a faulty temp sensor. You should have the computer scanned for trouble codes and check the sensor operation.
Also make sure the radiator is full of coolant.

SOURCE: Check engine light comes on but I do not know what to check. I did check the gas cap several times put it on again but the light stays on "check engine"

Take a battery cable off to reset computer then put cabel back light should go off if it comes back on have the computer scaned it shouldent cost you any thing tray it you'll like it happy new year. Kcp