I changed spark plugs and wires in my 97 ford mustang. Why is the check engine light still on?

The "Check Engine" light will come on for stupid stuff some times. It could be a serious problem or it could be something as silly as you did not secure your gas cap properly. Only a service center that has the correct computer diagnostic equipment can reset the Check Engine light. You may need to see your local dealer.

Take your car to any car parts place and get them to pull the codes from your car. That will help you decide what to do next. Changing spark plugs is good but there's an awful lot more going on inside that engine. And in light of how things are going, the spark plugs aren't the problem. The CEL (check engine light, for future reference) is only telling you that the computer has detected a variance from what it expects, and has recorded what the source of the variance is. And once YOU know what it is, you can take appropriate steps to fix the problem and then cancel the CEL. When the CEL light comes on, don't just start replacing stuff. Get someone with a scanner to pull the codes for you, then you can attack the problem quickly and economically.

This sounds like it could be one of many possible things, from a bad distributor to something as simple as having a couple of plug wires on the wrong plugs. Take it to a mechanic; they can diagnose it in a few minutes and give you an estimated cost to fix the problem. Don't guess at the problem. Good Luck

When the computer stores a trouble code it will not go away be itself. It must be cleared. Go to Auto Zone and they can read it for free to see if the plugs were the problem..doubtful, but if so they can clear the code or tell you what is going on to find what is setting the code.

Don't spend any more money until you find out what that code is for.

Good Luck

You prob have a bad misfire on one side, or like you said fuel mixture, but you would have to read the code to know, take it to autozone, they will read it for free, then put the code here to find out what to fix! If your cat is glowing, you prob shouldnt drive it til thats taken care of. Did you change the timing lately? possibly firing out the exhaust?

Probably need to buy one of those hand held devices for reading the codes to see what the computer is telling you.

Check to be sure the spark plug wires are correct, could be mis firing.

Places like Autozone will often let you use an OBD2 scanner for free.

Get the code, then you may be able to find out what's wrong.

Sounds like an HO2 sensor. (an oxygen sensor) You have two before and two in the catalytic converters.

maybe the catalyic convertor is plugged up with corrosion, its illegal to take them off. but alot of people do. one way u can tell is you will smell something funny. also you can get those little diagnostic plug in computers for like 40.00 and it will help you figure out whats wrong.

stop driving it and get it checked by a pro... nobody here can diagnose a running problem... we can only suggest throwing parts at it and maybe someone will be right before you go broke.... cheaper and easier to take it to a very sharp technician who comes highly reccomended by other ford owners in your area.