I went to Autozone to pick up a battery for my gf's car. On my way home I notice that I'm not getting alot of power. I notice this on a 2nd gear pull onto the highway my car won't reach 5k, its like a gradual rev limiter on my car. I limped it home, power is all there below 3.5 k I'm not throwing any codes. Idle sounds like there is a small cam in the car, sounds like its loping a bit. Any ideas?