I have been having engine codes lately... P1457 Evap Valve I waited a week and the light went out. 2 days ago got another check engine light... codes P0420, P0300, P0302 and P0303. Yup drove it to work it was really rough in the beginning then smoothed out. Got home, changed the oil, filter, air filter still runs rough but not as bad. Thinking of changing the coils ($50 ea) or should I take it in to the shop? I have little or no money and would like to fix it myself. Other things 275,000 miles all highway, drive it 150 miles a day. Uses oil, most of the time get good gas mileage. Had the head gasket replaced 2 years ago ($2000)...Any help!!!!

 

You're getting the P0420 (Catalyst system efficiency below threshold) because of the random misfires (P0300) in cylinders 2 (P0320) and 3 (P0303). You fix the mis-fires and the P0420 will go away.

First, 1 cylinder at a time, switch the spark plug in the mis-firing cylinder(2 or 3) with the spark plug in a non mis-firing cylinder(1 or 4) and see if the mis-fire follows the plug. If it does, change the plugs. If it doesn't, do the same procedure with the fuel injectors and change them if needed.

You really need a service manual. You can get a download, CD, or used one pretty cheap. Or you can get a new one here: http://www.helminc.com/helm/homepage...vlB&usg=AFQjCN

 

I just went out and had the engine codes checked and now it is only P0420. Is there any component that is involved with this code that is located on the back side of the engine on the driver's side? It appears that the oil from the head gasket leak from a couple of years ago was not clean off. I can see wires and was wondering if any are to the EVAP sys? Thinking of using Gunk to clean that area and see what will happen. I did change the spark plugs (NAPA parts) the 1st ones did not look bad. Changed the oil. It runs better but sometimes returns to the rough idle (maybe misfire) working on changing the coils next. Need more suggustions. thanks

 

Tap the catalytic converter very lightly. If you hear rattling then replace the cat and O2 sensors. If you don't hear rattling then replace the O2 sensors. I would suggest OEM as some people haven't had good luck with aftermarket. Luckily you have the narrow band cheap sensors instead of the wide band $200 sensors.

 

I got mine from oxygensensors.com for my 2000. The lowest cost I found for OEM (with plug) was around $200. They had a 'universal', which was exactly the same from the same manufacturer without the plug for less than half the cost. All I had to do was splice the wiring on the sensor to the OEM plug. Been going strong for 100K.

 

Here's the update: Spent the weekend changing plugs, ordered one coil (the thing that sits on top of the spark plug)(right?). It was still running rough but the more I drove the better it got. Went to PEP Boys to get the engine code read again. My goodness the P0300 codes were gone. That was Saturdary. Drove some on Sunday the car ran OK not bad but not the best. So thinking...I reset the engine code (battery cable). Cool drove it to work today. Ran fine. (75 miles). Start up to come home "engine light" going to check it tomorrow but bet it's P0420. Waiting for the engine to cool to check the cataylic converter time to cool. Gas is still good using the same amount. Oil is ok it usually burns oil. SO...

Changed plugs - old one did not look bad.

Just I get the coil and try it first

I am in California so smog here is different.

The 02 sensors are expensive - tell me again about which ones to buy

Cataylic converter - (magaflow??) with California is ~$430.

Second how long can I drive... the car is not due for smog until next year. Can I run it and save for a new car? Is there a point that it will not run. PEP boys wants $130 to check it out. I just cannot afford what will not work. In other words can I run it into the ground for the next 6 months?

Thanks again for all of your help...You have no idea how much I apprieciate it

 

The more you drive with a bad cat the more it hurts the engine, eventually burning out valves and rings and such. You can drive on it a little bit but, not a lot before it will start doing damage. Of course, I've seen people run a year with a bad cat and have no problems also. Better safe than sorry.

Cali requires OEM cats ONLY. They look under there and see aftermarket it's an automatic fail. Let's hope it's just the sensor(s).

Sensors are numbers 18 and 19: http://www.hondapartscheap.com/south...t=0&quantity=0

Or get the Denso(OEM manufacturer) here:http://www.rockauto.com/ They're even cheaper($35).

 

Ok I can not believe it. Engine Codes suck... Still on P0420 cat. conv. theshold limit low (bank 1) suppose to be my back exhast 02 sensor. Anyway been driving it (150 miles a day) runs ok. Went to get gas today 39.5 miles to the gallon... Maybe I won't fix it.

OK I here ya... there are 7 02 sensor to pick from got any ideas.

2002 honda civic ex
1.7 liter engine
4 cylinder
2 doors (driver side lock fell out - go figure)
4 tires

 

OEM is $70 or so at http://www.hondaautomotiveparts.com/...5=EXHAUST+PIPE

Most likely the old OEM sensor is by NTK. The part numbers at ngksparkplugs.com are
24291 Pre-Cat
24283 Post-Cat

Go to Amazon's search engine and put in {24283 sensor}. Either sensor is about $40 at amazon.com . I have bought denso and NTK oxygen sensors through amazon; no problems.