i have a 97 cavalier z24 with a 5 speed 2.4L engine. The car starts fine but when its not warm from driving, when i put it in gear and go it boggs down and tries to stall if i dont give it gas. even when i gave it gas it sometimes makes the bogging down worse. i replaced the air filter, fuel filter, cleaned throttle body, new plugs, replaced top piece that says 2.4L thats houses the plug boots and coil packs. problem does not happen whan car is warm. any ideas to what is wrong?