Good point. I was confusing the VSS for the crank position sensor. My LSJ has the vehicle speed sensor in the F35 transaxle, which should be unrelated to an engine misfire. The crank sensor does cause misfires, as I have had to fix that on my LSJ.
Well then, the
P0300 now looks like a better starting place.
Circuit/System Testing
1. Verify that the following conditions do not exist:
- Engine vacuum leaks.
- Fuel pressure that is too low or too high--Refer to Fuel System Diagnosis.
- Contaminated fuel--Refer to Alcohol/Contaminants-in-Fuel Diagnosis.
- Restricted exhaust system--Refer to Restricted Exhaust.
-> If you find any of the above conditions, repair as necessary.
2. Ignition OFF, remove the ignition coil from the misfiring cylinder, leaving the electrical connector connected.
3. Install the J 26792 to the boot of an ignition coil and ground.
Important: An erratic or weak spark is considered a no spark condition.
4. Attempt to start the engine and observe the J 26792 . The spark tester should spark.
-> If there is no spark, refer to Electronic Ignition (EI) System Diagnosis for diagnosis of the ignition coil.
5. Ignition OFF, remove the spark plug from the misfiring cylinder. Verify that the following conditions do not exist with the spark plug:
- Gas, coolant, or oil fouled.
- Cracked, worn, incorrectly gapped--Refer to Spark Plug Inspection.
-> If there is a condition with the spark plug, replace the spark plug.
6. Exchange the suspected spark plug with another cylinder that is operating correctly.
7. Operate the engine under the conditions in which the misfire occurred. Observe the Misfire Current Counters with a scan tool. The misfire should not follow the spark plug exchange.
-> If the misfire follows the spark plug, replace the spark plug.
8. If all conditions test normal, test or inspect for the following:
- A lean or rich fuel injector--Refer to DTC P0201-P0204, P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P2146, P2149, P2152, or P2155.
- An engine mechanical condition--Refer to Symptoms - Engine Mechanical.