Saturn Check Engine Light With Misfire Code

vacuum_test Saturn check engine light question:

This Saturn check engine light came when the engine has a miss all the time and scanning for the fault code, I got P0301 misfire at cylinder #1. My daughter just bought this 1999 Saturn and has a 4 cylinder motor on it. When I did a quick tune up, these are what I found:

  • Cylinder #1 spark plug looks pale compared with the rest
  • Cylinder #1 has a good compression which reads the same with other cylinders.
  • Cylinder #1 has a good blue spark color
  • When I tested the engine for vacuum leaks, I did not find any and blocking the throttle body air intake passage, the engine quit which to me indicates no vacuum leak. What other tests can I use to fix this Saturn check engine light fault code?

    Saturn check engine light ATS suggested fixes:

    When testing this Saturn check engine light misfire code, you should also try the following:

  • Swap the fuel injectors at #1 cylinder with any cylinder and see if the misfire code will move to that cylinder. I am assuming this engine has individual injectors for each cylinder, other wise you have to check your fuel pressure.
  • Have you swapping the spark plug wires? If you switch #1 spark plug wire with #3 cylinder and the misfire move to cylinder #3, then you know the fix.
  • Try swapping also the 2 ignition coils for this engine engine. Again if the misfire code move to another cylinder, the ignition coils are suspect and has to be checked or replaced.
  • Sometimes, to get an accurate status of the engine condition, you need to performed a cylinder leakage test for the engine. This test is more accurate than compression test and will give you an exact picture of the cylinders. A normal cylinder leakage test is around 10 to 30 percent. Any reading higher than this can indicate a faulty cylinder valve which otherwise cannot be detected during routine engine check ups.


    You can get a one on one online assistance on the above tests so you can do it properly. This is especially important when you need to know the various Saturn engine specifications which you need to conduct the test. Feel free to leave your other ATS questions on the comment box below.

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