Car engine bogs and stutters when pedal is pushed to the floor. Once or twice it has backfired and started to stall, caught itself and stutters and lacks power to gain speed.

Replaced starter, tps sensor, plugs, ign mod, coil, fuel filter, ckp sensor, ckd bat, cleaned fuel pressure reg, ckd timing chain. Still wont start almost eith gas pedal to floor help

Car will not start unless gas pedal to floor somebody please give me some advice on problem. Thanks.