Q: Cranks and runs rough have to keep foot in gas to keep running. Has new fuel pump and died while driving after pump was changed

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Changed the fuel pump last week after it went out and saw the vent valve on the fuel tank had all of the nipples broke off. Got a new tank to change it but haven't changed it out yet. Noticed the water pump was leaking water the other day and drove it home to fix the tank and pump issue and the truck shut off a half a mile from my house. Finally got it cranked up and limped it to the house. Changed water pump, thermostat and oil this morning cranked the truck and it is running real rough and have to keep my foot on the gas to keep it running. Also has a slight knock in motor. I am at a stand still on what could be wrong

My car has 175000 miles.
My car has an automatic transmission.

Check fuel pressure. There are only three possible explanations: a fault in fuel supply (plugged filter, injectors, etc.); ignition system problems; and air induction including the idle air control valve, throttle position sensor, mass air flow sensor and vacuum leaks including the PCV and EGR systems. If obvious, and easy to check, possibilities do not reveal the fault, the recommended service to request is a rough running diagnostic and the responding certified mechanic will travel right to your location and get this diagnosed and resolved for you. It is also possible that diagnostic trouble codes have set and the mechanic will attempt to retrieve those using an appropriate scan tool. If you have further questions or concerns, do not hesitate to re-contact YourMechanic.

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