6.0 diesel has been hard to start. Turn switch off and on 4 times to eventually start. Now with 2 new batteries it wont start and only turns about 2 revs. Egr delete just installed with complete kit. Had fuel leak on side of fuel filter housing. Replaced o ring. Not cam sensor because tach works while trying to crank. This is my sons truck to work and back dont know what to check next. Can you please help. Thanks.