2000 Mazda Miata, check engine light comes on. Code PO420

The easiest way to reset a check engine light on almost any modern car is to disconnect the battery wait five minutes and connect it back up. This will not tell you why the check engine light came on. For that you need a ODBII scanner, but if the issue was a gas cap left off and you have fixed that, then check engine the light should go off. I have found that many auto parts stores will read your car's ODBII codes for free.

First off, flashing is a warning NOT to drive it-unlike a steady CEL, flashing indicates there is a problem that needs immediate attention. When you had the CEL before, did you get the actual code? It might still be related, or could be an entirely different issue, although it is now more serious. If you can, you should drive it very little and straight to a commercial auto parts store to have the computer scanned for code(s)-WRITE the actual codes down, very important, so you can get help for your issue. Pay particular attention to engine temp, how it runs, check oil...do not drive it if it is running hot, has little or no oil, or is running really bad, get it towed-not worth the risk in ruining the engine.

Hi, the check engine light will require you to have the engine CPU scanned for trouble code's. This can only be administered with the assistance of a diagnostic computer scan tool OBD II. You can purchase this tool, at your local auto parts store, or you can just have the scan ran at your local auto zone parts store, free of charge. Once the diagnostic scan is administered, you will be able to isolate the issues that have caused the check engine light.
This scan tool will display a print out code and the location of the issue, on the engine, as well. There are Many issues that will cause the engine light to illuminate, but the most common cause will be a failed monitoring sensor, or sensor harness failure(separated power wire, or ground).
After retrieving the code, it will be interpreted to know what caused the lights to come up and that will be used to fix the problem.

Good Evening, there are several automotive stores like autozone or advanced auto parts that offer the service of scanning your check engine light for free. It would be very worthwhile to have them do that and retrieve the code or codes that caused your light to come on in the first place, from there we can point you in the right direction for repairs. Hope this helps.

What is the code, you need to have a scanner hooked up to read it. That is your first step. (Some auto parts stores will read these for free, but will not give you a lot of information.)

get the vehicle scanned for the trouble code most auto stores such as auto zone/advanced auto scan for free check ur local area the check engine comes on when the computer senses a problem or something is not reading right if u want when the code is read the store or mech can and usually do reset the computer

blinking light means engine is misfiring. continuing to drive will severely damage the engine. The O2 should not be related to your engine misfiring

It depend on the code. there are a lot of things other than the O2 sensors. Have it scanned and bring the code back to this sight so we can tell what the problem is.

Most Advance and Autozone store will scan it for free.

Hope this helps

you'll hjave to get the vehicle scanned for codes. it could be a variety of problems. eg. egr, O2 sensor . without scanning it for codes you could be replacing may different parts in your vehicle. take it to a repair shop where they have the equiptment to check for codes.

se if egr is controled by vacium or electric
if it is by vacium then locate the egr solenoide and make sure it has vacium in one hose w/ engine runing if it does then replace solenoide