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1997 Toyota Corolla Question: My car code is P301 (clogged fuel injector or spark misfire)

 

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caribe, 1.8L 4 Cylinder, Kernersville, NC, August 31, 2010, 13:22
 Rookie

The engine light went and and off, but then the car was flooded and the light has been on since then. The car's motor oil, transmission oil, break fluid, spark plugs, air filter and computer were replaced. I added fuel injector cleaner twice. Then I changed the cables + rotor and the engine top seal (just to stop oil leak due to normal wear)I also cleaned the engine oil with a solvent and changed oil and filter after changing the seals. The car has about 150,000 miles and the engine runs smoothly even before these changes. The code P301 is still on, although I erased it by disconnecting the battery after all repairs. Do I need to replace the spark plugs again? (they look carbonized, but the tips are intact)(Maybe the motor needed further drying before replacing the spark plugs). Is there a sensor(s) that needs to be cleaned with an electronic spray cleaner to solve this code? bond@caribe.net

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  • Answer #1

    August 31, 2010, 14:16
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     Master

    I would do a compression test in the number 1 cylinder. A P0301 is a misfire code for the number 1 cylinder ( there is no P301, OBD-II codes are 4 digits )
    The compression has to be at least 140-160 psi. Also check your valve adjustment after 150k, the valves need adjustment, or they will stick slightly open and cause a misfire. intake .006 " - .010 " exhaust .010" - .014 "
    VERY IMPORTANT!!

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