I diagnosed it by trading wire 1 and 5 at the coil,and the code changed to P0301. In short: take the P0420 code seriously and give due dilligence to figuring why it has been logged. Not sure why my car would not start my husband changed my fuel pump and then turned out to need a new engnition coil. First an intermittent misfire after an highway trip then idling for 20 min. I also change the spark plug not the wires. To my surprise, both my radiator and reservoir tank had no water and was empty. Again Check for rhythmic spark.
Things have been fine with alternator since then. Was and in injector cleaned with gumout runs great now! Only rough idle in drive when stopped at traffic light for example. I want to convert my 1980 Buick but I don't relish the thought of running a whole second fuel line back to the tank and drilling a hole in my tank or buying an appropriate tank. Am I destroying another expensive Cat. I have a friend who had a P0420 on a '99 Dodge 1500 and it also wasn't running right.
This is base on 80%-90% hwy driving and more. I replaced the down stream O2 sensor. My wife's 98 grand am 3. Listen to the injector with a stethoscope, long screwdriver, or other long rod, and compare it with another. P0135 - Heated Oxygen Sensor Circuit - Bank 1 Sensor 1 This code indicates a problem with the front oxygen sensor on bank 1. Now my check engine with P0420 code. I am a auto tech with over 25 years experience, there are a few things everyone here needs to know.
As the wise indian once said, look for signs,i hope this helps Things you might want to check,ok you know there is a problem on the left side, the first thing i would do is pull the plugs on the left side bank i and see how they look,things that it could be are a bad wire,bad plug,leaking intake manifold on that side,leaking exaust manifold on that side or like in my case bad exaust valve seal or to much blowby in a cyclinder on that side, whitch would show on one of the plugs looking oily than the rest on that side but you said you didn't see any smoke so we will rule that out,so plugs would be a good place to start. Check under the hood and car for any air leaks, such as intake manifold, vacuum hoses, exhaust manifold, exhaust leaks 2. If there is rhythmic spark then the 1 Wire is fine. Cat conv are pretty expensive and I'm trying to check other posibilities causing the problem before I have to change the Cat. Just because the injector is ticking doesn't mean fuel is flowing through it. After the converter was changed, I drove it really hard to see if the problem was fixed. Two days later it was back on.
I plan on trying a good fuel with the least amount of ethanol in it, and then a good fuel system cleaner. Make sure the vacuum hoses going to the valves on the front and rear cylinder banks are connected and the hose s not damaged. Use it for about 3 month, then Check engine light is on, scanner said code P0420. A weak battery or starter can also trigger this code, so check those first before replacing any other parts. Thanks to the Internet one forum guy was like intake leak, check your manifold for cracks and or bad gasket, but I did and I did not appear to have a leak, guy responded do it anyways I'll put money on it not really gonna happen right? Maybe I need to torque them down more. Then, replace the coil pack going to that cylinder.
Car runs great but I warm it up in the morning if it is hot early I turn the air I see the temperature gauge drop from being in the middle of the hot an cold to almost cold bottom an slowly but surely or never goes back to the middle an just today I got a check engine two Weeks ago my mechanic said fill up on 91 an I have been doing it ever since been great I dont know tomorrow I will see what the modus or whatever the snap on tools name is theh use at his shop. But my problem is the car gives out poor mpg 19-20, sometime 21 if I'm lucky. I seen other get 30 mpg+ on their crv on hwy. Always make sure the basic maintenance is done first and that things such as the fuel filter, air filter, spark plugs and spark plug wires are in good working order, as these are all possible candidates for a problem. I called and after talking to them they sold me a cat. I recently replaced the motor in this truck. Replaced 2 ignition coils and all spark plugs after repeated misfires.
I took it back demanding an explination. I then bowed down to the stealership and paid an arm and a leg for a stock cat and all is good now. Can anyone fix this car correctly so i don't have to buy a new car. Can any one please help me! Took it to a shop called Buckys,he removed the o2 sensor and said that by doing that he could tell my cat was not great somehow. Call them and they might help as in october I was having panic eppisodes over this as my car was almost side lined due to pa inspection. Try that and let me know what happens Thanks So many people needing help and so few answering! I then got frustrated and running out of patience. There are places like ebay to buy cheaper sensors but those may be cheaper because they break every year.
I do not want to drive the truck running rough like this and am getting sick of paying mechanics to throw parts at it. Remove the cover to reveal the ignition coils and spark plugs wires. Misfire is usually caused by spark plug wires first, spark plugs 2nd, and coil third. Replaced fuel filter, another 100+ miles and the light came back on. The wiring harness on the new motor was short for reaching the 02 sensor in the rear of the cat.
I would appreciate your suggestion and thanks for your website. Some help would be appreciated please! I change the spark plug wires and noticed a big difference in power. I replaced all gaskets, did not help. Please help asap my smog is due now. The signal is used to control fuel cutoff to lower engine speed. Afterwords I made a considerable mileage So far I never see the check engine warning again :D my truck is a 2005 expedition.
I'm at my wits end here. . I believe my intrigue is mpfi but not 100% sure. No other codes were being stored in the computer's memory. In other words a rich or lean fuel code. My service engine light has come on and a mechanic hooked it up and said it was Bank 1 Cat. P0420 catalyst efficiency below threshold bank 1 My mechanic said he would remove the catalyst convertor in front which he did.