trouble codes for multiple misfires

Cylinders 1, 3 and 5 are on the left bank. There could be some problem with the cam symchronisation or other causes. With a V6 engine, misfiring might not be easily detected by the driver as the performance might drop only slightly.

How would I troubleshoot this possible cause and if it turns out to be the culprit, how is it fixed? Every time I reset the codes, I can only drive it a short distance before the check engine light returns with the same codes, obviously because the problem hasn't been resolved althought I've tried everything I know to try and am at a loss for where to look for the problem.

Was anything done prior to this occurring?

Did you test the compressions?

I had received the vehicle as a gift and it seems to run fine. I have not replaced any parts or performed a compression check, since it sounds and performs well. Does this vehicle have a "Spark Sensor" that could be faulty? I'm not sure how that works but someone mentioned that the spark sensor could indicate a misfire even if falsely detected. Where would I find it if one exists?

If there were a compression issue, wouldn't that be a consistant problem and affect engine performance? I can drive fifty miles or more before the check engine light returns.

A compression test would allow you to know if there are anything wrong with the valves and timing. Misfiring might not occur consistently and there are many possible causes.

Fuel delivery, valve and cam timing, vacuum leaks, camshaft and crankshaft position sensors are possibe causes.

The 3.9 L engine has the camshaft sensor in the distributor so it is not likely for it to be the cause as it would be all 6 cylinders that could be misfiring, so would the crankshaft position sensor.