1997 jeep wrangler

i have a 1997 jeep wrangler sometimes it run great sometimes it runs terrible spitting and sputtering can barely make it down the road and gets terrible gas mileage the check engine light has been on as long as i have had it i took it to autozone and they put their computer on it and said it showed something wrong with the brakes but they seem to work good please help

When was the last time you replaced the spark plugs?

that did not make any difference at all

You need to report everything that is or is not up to date about the maintenance - so n addition to spark plugs - wires, cap/rotor (if applicable), fuel filter, air filter, etc.

When was it that you had the codes read? I would do it again to see if there are any others.

everything is up to date the code has been read 2 times with same results

A lot of people think that “everything is up to date” but then further info often shows that it isn’t. Can you dig up some specifics, like “plugs X miles ago; wires X miles ago…” It is also the case that certain components aren’t normal maintenance items but do become likely candidates after a certain amount of miles/time. How many miles are on the vehicle?

What was/were the actual code(s)? “something wrong with the brakes” is not something that the ECU will report. There are a couple of codes having to do with brake switches, such as that associated with cruise control - but a code can’t tell you that something is actually wrong with the brakes - unless its about an ABS system but that should be a separate light. The check engine light codes will be in the form of a P followed by 4 numbers such as P0123.

You have to understand that you posted a question that basically just says “My car isn’t running right. What is the problem?” Well…there are lots of things that could be the problem.