I have 2008 expedition with 5.4 triton that has been a great vehicle. I have been fighting a persistent p0305 code. Routine maintenance has been regular.

Timeline:
Code p0304
Replaced #4 coil and plug 16 July 2012
Fuel injectors cleaned 16 July 2012
code 0301 0302
Replaced #1, #2 coil 19 July 2012
code 0303
Replaced #3 coil 2 September 2012
code 0305
Replaced #5 coil 20 Nov 2012 @309,000 miles
Still having same 0305
Cleaned throttle body and 7 Feb 2013
Still having 0305 code
Cleaned 5 and 6 Fuel injectors. Resolved 0305 code 12 Feb 2013
Replaced failed Alternator 3 Mar 2013
Code 0305
Replaced Brake Booster 20 May 2013
code 0305
PCV Hose Driver Side 25 May 2013
Code 0301 and 0305 AC quit working
Replaced #1 Coil. Cleaned MAF. 25 May 2013 AC now working. 340,000 miles
code 0305
Replaced 2nd PCV hose June 7 2013 342,100 miles.
Code 0305
Replaced Fuel Filter 13 June 201
Cleaned MAF
Code resolved for 2 days then returned
Replaced #5 coil 21 June 2013
Replaced all 4 O2 sensors 22 June 2013
code 0305 returned after 2 days
346,000 Plugs Motorcraft 515 OEM and Repositioned coils 7 July 2013

Now I have no code. Yay! Except that there is still shaking when idling in gear. Put it in neutral, the shaking stops. It also occurs when accelerating, particularly prior to shifting. Once it shifts into whatever gear, the shuddering stops. It seems to have good power but lousy gas mileage. No pending codes. I have not replaced the master cylinder, but already have it because the ABS sliding car light comes on for no particular reason. Have checked all the brake lines for leaks. Not losing brake fluid.
I expect the dreaded 0305 code any time now!
Exasperated! Help!

 

Check oil pressure cold and hot. Use a real gauge. You may have low pressure when hot.

 

Ok. Will do. Thanks!