Full Press Gas Pedal No Acceleration

2008 Laredo 3.7 V6 130K miles - problem is exactly as listed, full gas pedal, no acceleration. RPMs seem capped at 2,500. No odd noises or sounds coming from the car.

No check engine light upon start-up. No other lights. I frequently change oil.

Car was recently giving me P0300 code for random multiple cylinder misfire. The car would rough idle like crazy, or ride rough when driving slow/ slowing down. But the misfires seemed to stop after some throttle body cleaning and fuel additives.