2005 Impreza cranks well but starts poorly
My Subaru has a new battery and the alternator output is correct.
When I turn the key I can hear the fuel pump prime and it cranks like a
champ.
But it usually won't start unless I boost it with another vehicle - at which point
it starts instantly.
Once running it is perfect.
So I'm a bit confused - it can't really lack of spark because the car runs
perfectly. And it can't be lack of fuel because it runs perfectly...
I'm thinking it may be something with the fuel pump however, and maybe the
extra boost gets it over the hump? Or possibly some grounding issue with
the fuel pump?
Do my assumptions sound reasonable or what might I be missing?
Thanks.