If the air can't get into the cylinder to get compressed...? I would think that if a cylinder or two are not funtioning properly on a 4 cylinder (loss of efficiency), that might explain why it is down on power. That was my experience. I didn't ask for it to be my experience. The service manual mentions frequency of combustion chamber treatments to be important. We just have extremely poor quality gas in Canada. There must be some sort of reversion problem with the center cylinders that the engineers knew about and chose not to fix until they got away from throttle body injection.

Too many cars, too many parts, too little coin, too little space to work in, too little time left to make it all happen! Update: down to one ride, still too many parts, a little more jingle in the pocket, gaining space, and it's going to happen this year!