cel help
 

hey everyone, new here but frequently browse the forum, i recently bought my 1st car and its a 2000 acura integra ls non vtec and all was going well until today when my cel came on so i plugged in a scanner and got the codes
p0420 - catalyst system efficieny below threshold bank 1
p0300 - random / multiple cylinder misfire detected
p0302 cylinder 2 misfire detected
p0303 cylinder 3 misfire detected
p0304 cylinder 4 misfire detected
i just changed the spark plugs, but not sure where to start next. any help is appreciated

Re: cel help
 

Does the car run?

If so, does it run well or poorly?

Random misfire is often a fuel issue, so the first thing you do is pull the spark plugs and inspect them, Google "spark plug chart", what the ends of the spark plugs look like can tell you a lot about what is going on in the engine.

The second thing you need to know is, what is the fuel pressure, so check it, best way is to install a fuel pressure gauge, permanently.


This can just as easily be a spark issue, but that is another set of tests.

A good troubleshooting practice is to check and eliminate the simple things first as the possible problem.

Hint number one
If your going to work on your car yourself, pick up at least a Haynes manual, it will make your job a lot easier. 94

Re: cel help
 

car seems to run solid but okay ill check those out, thanks alot!