GM Repair Questions? Ask a Mechanic for Answers ASAP
So the P0305 was FIRST, then AFTER you swapped coils, P0300 came up?
Ok. Let's concentrate on the 305. I believe that is going to be the source, and when you swapped coils, the computer was a little confused as to why the misfire on 5 was no longer there, and suddenly jumped to another cylinder, which produced the 300.
Remove the coil that was ORIGINALLY on cylinder #5 before you swapped it. Remove the spark plug (check the plug for visible cracks/diode wear) and insert it into the bottom of the coil. Hold the coil with the plug in it near a solid ground (ie. the block) and while cranking, see if spark jumps (careful not to get your hands to close to the spark, they bite pretty hard). If no soild, even spark, suspect faulty coil. If there is spark, we'll move onto another test.
No prob. Take your time. I'll be here and the thread remains open for another 23+ hrs.
Looks like you've got a faulty ignition coil. It's actually pretty common, and fairly inexpensive to repair.
Stay away from Auto Zone electrical parts! You'll be doing this job again in 6mo with an Auto Zone coil!! Go with NAPA!!
Hahhahaha! No worries! It's all good. Take your time!
Excellent! Glad I could help!
To clear the code, you will need to remove the "NEG" cable from the battery for 15min.
Anytime! Glad I could help! Have a great day!