P0420 Error code, I had the sparks plugs replaced in dec...now one is misfiring again.
I have a 2001 Jaguar S-Type 4.0. My car failed emmissions because of three error codes. P0420, a misfire (don't have that code), and an error about the O2 sensor in bank 1. I had a tune up in December 2008. The error codes disappear. My car now intermittently stutters when I accelerate. The last time that happened the spark plug needed to be replaced. Does this happen often? I took my car to National Tire and Battery. Since its under warranty, should I just get the spark plugs replaced again. Is there a way to tell if there is a shortage or something? The reason I ask...I notice that the car really stutters when it rains..but does it less when its dry. Sometimes, when starting my car, its takes a few cranks to start up. What may be causing this? I also hear a ticking noise, but the ticking isn't as loud AFTER getting an oil change. I have my oil changed at NTB as well. Should I be adding some kind of hi mileage oil to my engine? Please advise. Thanks in advance.
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Re: P0420 Error code, I had the sparks plugs replaced in...
I dont know if this 402 code is a miss code on a jag but usually miss codes are p0300 codes. if you are hearing a ticking and you own a spray bottle, an old mechanics trick is to mist water on the plug wires while the engine is running preferrably in the dark.
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MISFIRE ON CYLINDER 6 COULD BE FAULTY SPARK PLUG OR BAD IGNITION COIL OVER THE SPARK PLUG,YOU COULD HAVE HAVE CLOGGED FUEL INJECTOR.CLEAN ALL FUEL INJECTORS USING A CAN OF SEAFOAM TO 3/4 TO FULL TANK OF GAS SEE IF NUMBER 6 MISFIRE CLEAR UP, IF NOT COIL OR FUEL INJECTOR COULD BE AT FAULT.ALSO CHANGE 6 SPARK PLUG FIRST.BEFORE BUYING NEW COIL OR FUEL INJECTOR THAT WAY YOU KNOW PLUG NOT THE PROBLEM.
there are a few things that set this code.a bad spark plug,a bad spark plug wire,a bad ignition coil,a bad fuel injector(either not working or very dirty),a compression problem(either poor valve sealing or piston assembly problem),a vacum leak at cylinder #1,the rule of thumb is you need 3 things for a cylinder fire,spark-fuel-air.
Catalyst System Efficiency Below Threshold Bank 1 P0300=Random/Multiple Cylinder Misfire Detected P0301=Cylinder 1 Misfire Detected P0172=System Too Rich Bank 1 P2181=Cooling System Performance you need to write these down,have someone clear the codes in the car,then go for short ride and recheck which if any code reappears.it's like domino's affect,one sensor can start a chain affect with the others.
Check the igniter module. I assume you have a ecu code telling you #3 coil is missfiring ? If so also check the crankshaft angle sensor . If it is not an error code do a compression test and check the injector. Hope this helps Regards George
i also have the same problem regarding the oil leak. this is due to the spark plug gasket leaking and you will need to replace them. they are circular gaskets about 1.5 inches across that fit to the underside of the rocker covers and prevent oil from seeping down the long spark plug hole. when i investigated my leak i assumed it was just the rocker cover gasket that was leaking but once everything was removed it is obvious.
misfiring can cause a P0420 code.
I would recommend a set of honda plug wires and plugs if the P0420 code returns.
I have used bolt in aftermarket bolt in catalytic converters but don't remember the brand name they fit ok and i have had 1 or 2 return with a P0420 code out of about 20. I have never replaced the oxygen sensor on a civic like yours.
I always fix the misfire problems, reset the computer, and have the customer drive it and see if the code p0420 returns. 50% don't have the P420 code return. drive it and see what happens and go from there.