Developed a miss while on the road. Got back home,, and checked codes. I had a P301, # 1 cyc misfire. I changed the plug and the coil, then cleared codes. restarted, engine light came on again. Checked codes and got the P301 and P2302 (Ignition coil # 1 secondary circuit insufficient ionization). Any help would be appreciated.

 

How did you "clear" the codes? Do you use a scanner, or do you use the battery disconnect method?

How is the connector/wires that hook up to the coil on cylinder 1? What spark plugs do you use?

Most common causes of P2302 are below. If you replaced spark plug and coil, you probably already ruled out the first two.
-Bad spark plug
-Bad ignition coil
-Ignition coil 1 harness is open/shorted
-Ignition coil 1 has a poor electrial connection (harness)

Worst case scenario, I have heard of a few cars needing new PCMs for these P230x codes. However, thats a long stretch, as those that need a new PCM usually get a P300 as well, not just a one cylinder misfire.

 

used a scanner to clear codes. Just picked up a set of Autolite plugs to start with. Parts place said to gap at 0.035. Sticker under hood said 0.040 so that is what I went with. Old plug is a NGK ZFR6F with gap at 0.060, with probably 40,000 miles on it. Also checked resistance of old plug 7.8K ohm, with new plug reading 3.7 k ohm.

 

Just for grins, tried a couple of different combinations. Old plug/new coil, new plug/old coil, new plug/new coil, and old plug/old coil. Any combination with old plug gives me a P301 (cyc 1 misfire) so plug is bad. Rest gives me a P2302.
Next step, got into shop manual and checked, all hot leads for # 1,3,5 are connected to one wire, all hot leads for # 2,4,6 are connected to another. Both of these wires are connected together and go to the same contact on the ASD relay. While running, checked for voltage on the hot coil lead on # 1 and # 3. Both same, approx 13 volts.

Then it was time for some brain lubricant of the 12 ounce type.

Decided to get in deeper the next day. I wanted to see what the switched ground to the coil looked like. Hooked up an o'scope to cyc # 1 and to cyc # 2 for comparison. I have a different looking signal when comparing the two. Just for grins again, switched to cyc # 6 and it matches what I had on cyc # 2. So for now it appears that it is either wiring on switched side of # 1 or the PCM.

Plan on digging a little deeper, but looks like a trip to the dealer.

 

Been reading a lot in the manual. Found a description of what I saw with o'scope hooked up to # 1 coil. Lol, found it under # 1 injector problems. "No inductive spike detected...." .
Been a few days since free time to work on truck, so out I go after coffee and etc.