1. That sounds about right

2. That much drag does sound extreme. Maybe your compressor/clutch is going bad. Too much refrigerant could cause extra drag but shouldn't be that much (that would probably just keep it from cooling properly). The compressor seized up on my Amigo & I just bypassed it with a shorter Serpentine Belt. I never did go back to try & find out if it's the compressor itself or the clutch.

3. Start with the easy/cheap stuff first like spark plugs & fuel filter. If those don't solve your problem then move on to the more involved things like Fuel Pressure Regulator, Idle Air Control Valve, Exhaust Gas Recirculation System.

Keep this thread going with your progress & we'll help where/when we can.