Have not had the opportunity to do so on a 2004, but I have changed plugs on a '96, '00, and '07. They are essentially the same. You will need to remove part of the air intake system and possibly battery and windshield washer reservoir. Plugs are in a deep well and having an assortment of socket extensions and accessories is essential. A long-tipped angled needle-nose pliers always comes in handy to fetch the socket and plug from the well. If you have a well equipped tool box and you have changed spark plugs on other vehicles you should be set. Good luck!
You may have a bad valve, did you replace the rotor and cap? Check the cap for cracks.
gaps on all plugs should be .039-.043 inches
that would most likely indicate that your 3rd cylinder is not firing correctly or firein late A.E. "missfire" i would first check your spark plugs, to see if their good, and if they are i would check your timing
you dont
You have a four-cylinder engine with one spark plug in each cylinder.
how to change spark plugs on a 2004 Hyundai sonata 6 cylinder
Have a look at ; www.carbasics.co.uk
use a bendy extension with your plug socket on the end. Available in a good socket set such as Teng-Tools. Dan,
The spark plug gap, for your 2000 Subaru 2.5 liter engine, is .007. Most spark plugs will be pre-gapped by the spark plug manufacturer.
Generally, to replace spark plugs on a Subaru vehicle, the spark plug boot should be removed. Then, the old spark plugs should be removed using a socket wrench, and replaced with new ones.
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Follow recommendations in your owner's manual.