asking for help and troubleshooting ideas for hesitation, shuddering, and P0302 CEL on a 2009 2.5i Limited Legacy N/A.


Background:
2009 2.5i Limited Legacy non-aspirated (N/A), 4EAT auto trans that my daughter daily's. I did a headgaskets, water pump, idlers, and timing belt in May 2017 due to oil seeping from underside of heads. I also changed sparkplugs while engine was out (NGK FR5AP-11). Car drove well until SEP 2018 when daughter stated that car was shuddering and undriveable due to hesitation along with CEL. I read the codes and it had p0300 along with P0301-P0404. Started checking sparkplug wires and two of them had insulation break apart. New plug wires and an OEM coil were installed as one of the sparkplug wires broke off in the coil. Fast forward to NOV 2018 and shuddering, hesitation and P0302 are back.


I checked the interwebs and the usual P0302 troubleshooting came up. I did the following:
--I checked wires, all good.
--pulled the plugs on cylinders 2 and 4, checked their gap (0.040 in); and also their color. No signs of oil or running lean on the plugs.

--plugs re-installed with original plug from cylinder 2 installed into cylinder 4; and original cylinder 4 plug installed into cylinder 2. (I did this to see if the CEL would follow a specific plug).


Wife drove the car today and it hesitated and within 30 feet of driving she stopped and told me that the CEL had come on. Upon her return, I read the codes: P0302.


Tomorrow, i will do the following:
--check for any airleaks into the intake (post MAF).
--clean the MAF.

Addtional info:
--both CV boots are torn and I have OEM CV boots that I will install to repair the drive shafts. (Currently believe that this is not causing the hesitation or CEL as it is drive line not engine related).


What am I missing. What troubleshooting ideas can you provide.



cheers
rdleg05