If it was the clutch switch, or the starter, it wouldn't consistently start with a jump. An intermittent switch failure wouldn't be correlated with the battery.
Once it's running, does it keep running without issues? If so, the alternator is working properly.
I'd venture that it's either a bad ground, or an internal issue with the battery. As has been mentioned, even "brand new" batteries can have issues. Some battery problems can present as an intermittent ground. (I've twice had bad batteries that tested "good" at the local parts store.)
If it was one of the other grounds, it wouldn't consistently start with just a jump.
I strongly suspect the battery is the root of the issue.
Blue-ish 2006 2.4, Werks stage 1 turbo, Borla cat-back, DDM braces, Spec aluminum flywheel, Spec stage 2 clutch, Werks aluminum radiator, some gauges, RKSport hood, Morimoto FX-Rs, GReddy Profec, Norm's fenders
'07 GXP, RPM Stage 2, Solocatless downpipe, TCE Wilwood 6 piston front brakes, 4-piston rears , Stainless brake lines, slotted/drilled rotors, BC Racing BR coilovers, Performance Autowerks intercooler, DDMWorks CAI, charge pipes and braces
Last edited by raygun; 11-25-2018 at 03:25 PM.