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New to site but I've got problems with my work truck I recently bought a long block 5.7 vortec from summit. And I also bought the updated fuel injection setup I also replaced the fuel pump the mass air flow sensor and fuel filter. It ran about thirty min. And developed a hesitation when I come to a stop then I would have to feather the throttle and it eventually would snap out of it and accelerate normally. So today I drove about twenty miles out to a place I ride dirt bikes and it was the same thing hesitated at every stop light until I got back into town and stopped at the only light and then it started missing and sputtering instead of hesitating and it is strange because it idles fine soon as I try to give it gas it starts dropping one or more cylinders and it doesn't stop missing I checked the wires and distributor cap rotor they looked perfect I did replace the distributor when I changed the motor also so it has maybe 3000 miles on it as well as the motor fuel pump  water pump. I just changed the mass air flow with a new one last week. It's not showing any check engine light but I can barley get it to go. It misses so bad if I give it more gas pedal I intermittently back fires through the intake sounds like I'm am stumped I check the grounds I checked for vacuum leaks I need to get this thing running it's the only thing I have to drive for work.  And I took last week off to fix the rear axle and put new brakes on the van along with new fuel filter and. MAF SENSOR.  Please if someone can help it would be great to have this thing fixxed so I get my jobs finished thanks 

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