Saturday, November 20, 2010

Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?

2000 Honda Civic EX (4 cylinder) 159,000 miles.

I took it to Autozone and they told me it was code P0303. I did some research on line and so far this can be the cause...Faulty Spark Plugs, Faulty Spark Plug Wires, Coil Pack, Fuel Injector. The guy at Autozone told me that I should change the distributor cap, rotor, plugs and wires. Is changing all of this necessary? About how much will all this cost? Any ides as to where I should start? I don't want to start changing parts that don't need to be changed. I'm hoping it's only the spark plugs since I haven't changed them in years (I know!). Are these parts hard to it something I can do or do I need to take it to a pro?Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
My daughter does her own tune-ups on her Civic. These parts should be replaced more often than every eight years, sis (check your owners manual). The whole kit should be around $100, and it will save you money with the better gas mileage you will get.Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
Auto zone cannot always give you the exact part that is going bad. But the sad this is it can be any of those. Have you checked the gap on the spark plug, or ever had them replaced? Make sure that sprak plug wire is connected securely too. Hondas only have one coil, so if it was bad or going bad you'd know it. It only has one pack for all 4 cylinders. 2nd have someone check the distributor cap, as there could be some corrosion on the tabs inside and just needing cleaned off. If you take any spark plug wires off do 1 at a time that way you will remeber the firing sequence.Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
honestly the ODBII lights can light up if you have one misfire... the question is whether the car is running fine. If it is then dont' even worry about it...if you think you need spark plugs then change them and while your at it go ahead and change the plug wires.... but dont assume that the light knows all and tells all.... I've had the lights pop on simply because I washed the engine and then started the car before the engine was completely dry.Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
I would start with the plugs. However make sure you get NGK or Denso plugs, do not use AUTOLIGHT, CHAMPION or BOSCH plugs. The problem with trying to fix your car from a code is its only a starting point for what could be the problem. If it's been year since you changed the plugs how long for the cap and rotor? These also can wear out over time. The reason Autozone does the free scan is so they can sell you the parts to fix it so while he may be correct in saying re place everything, if your trying to save money start with the plugs and then the cap and rotor and wires last.I would not worry much about the coil if it was bad you would most likly have more than one mis-fire code.Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
Start with the least expensive thing or take it to a shop.

Start with the plugs they are like $10 if you can replace them yourself.

Very unlikely it is the injector.Engine light came on - Code P0303 Misfire in cylinder 3. Helpppppppppp.?
Never put a part on just because it could be a problem - diagnose first! First you should remove the 3 spark plug and check it for fouling (you should be able to find pictures of spark plugs that have been run under different conditions easily online if you've never done plugs before). If it is fouled, then you know it is part of the problem, but you don't know it is the problem. Next inspect the wire for carbon tracking, tears in the insulation, corrosion on the metal contacts or discoloration. Also check the resistance in the wire and make sure it is not too high. Remove the distributor cap and check inside for burns, cracks, carbon tracking and corrosion on the cap and rotor. Inspect the rotor button (metal contact) for wear as well and make sure the contacts inside the cap are in good condition. If you have done this in the past 30K it is unlikely unless your cap has a water leak or the wire has been installed but not run through the holders or damaged, but if it has not been serviced in a long time, spark is likely your problem. An injector check is more difficult. You can use a noid light to check injector pulse (make sure the wiring is working properly), but you may need to take it to a shop to check injector flow unless you have this equipment at home.

This is what your initial research missed. While it is highly unlikely that this is your problem because many engine problems present with noise as well as a misfire, I cannot let an internal engine problem go unmentioned as a possible cause. If everything else is good (or you want to skip the fuel system check because you don't have the equipment), you can get a compression tester or take it to a shop for this step. Remove the spark plugs and check the dry compression on each cylinder. If you notice a drop of more than 20% on cylinder 3 you've found your problem. Then you should do a wet compression test (add a SMALL amount of oil to cyl 3 and check the compression again). If the compression improves, the problem is the piston rings and if it does not it is likely in the valvetrain. Here's another part where you can get stuck without expensive equipment - unless you want to tear into your engine, if the wet and dry compression checks are bad you will need to do a leakdown test by pumping air into the cylinder on the compression stroke (valves closed and piston at the top of its stroke) and determining where it leaks out. If it comes out the intake, it is an intake valve problem, if it comes out the exhaust it is and exhaust valve problem, if it goes into the crankcase, it is a block problem and otherwise it is a warped/cracked head or head gasket problem. The head gasket is a very involved repair, but there are a lot of people that can do it themselves by sending the head to a machine shop to be inspected and installing a new head gasket and head bolts if the head passes inspection or can be machined. Most machine shops will do any valvetrain repairs you need as well. A block problem condemns the engine. The other problems are a cost analysis of whether it is better to fix or replace the engine cost wise. Since I can build an engine, I would likely fix it, but if I had to pay for labor I might reconsider that. Be sure to get an estimate both ways if it comes to that so you can see the difference in the warranty and price.

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