not enough compressor oil cause more engine loading when compressor kicks on?
 

I just bought a car that really is a dog when the compressor kicks on. It's a joy to drive when the A/C is off but I can feel it when it kicks on. I have my foot in it a good bit more and acceleration isn't near as good. It's not to the point where the car won't go, I don't want to over exaggerate the situation. But it's definitely very noticeable on the cars performance. It had the ac worked on at a chain tire shop just before the purchase and I have no idea if they added oil. I'm sure the system was opened and recharged. I'm curious if a lack of oil could be making things a little big doggy. I don't know a ton on A/C systems but it seems like this could be possible.

only way too little oil would make the compressor sluggy is if the crank is damaged on the comp. too much oil could be slugging the valves, too high pressure from overcharge could be straining the system, and a damaged compressor could be causing a HP load as well.
is this for the 190? how's it running? how much power does it have with the a/c off? what's your 0=60 time? you could be just out of time with the motor, and have a weak motor to start with, then the 20 or so hp loss from the a/c rears it's head.

Assuming the car is now using R134, you will find that switching back to R12 will noticeably lighten the load on your engine.