You may be at the limit - Give it a shot - Fell the plugs after the A/C has been running for an hour. If they fell hot. you probably need to re-do the plugs and connectors.
I use mine at home, but I can't run anything else when I run the A/C
2001 Coachmen Mirada (Ford F53 6.8L V10) - Toad 2001 Civic
It won't do MACH 2, but I can get a sandwich and take a pee.