Runs rough and dies

Discussion in 'F-250 and F-350 General Tech and Info' started by indybama, Mar 6, 2022.

  1. indybama

    indybama Junior Member

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    Hey yall, new to this forum. Ive been searching and googling every symptom my truck is doin with no help. So im in hope yall can help me, im at my wits end with this thing. It sat for 15 yrs due to a bad fuel pump. Ive been driving it for over 6 months now. Ive put lucas, sea foam, n berrymanns in it n i run 89 fuel. My uncle gave it to me before he passed away 2 yrs ago.

    Its an 87 f250 5.0 4 spd 4x4. Its starts n runs great when its cold. If its cold outside, 30s-50s, it runs perfect. When its 65+ outside, it starts cutting out and popping back in the intake when it gets up to operating temp. I put a new fuel pump in it, the one on the frame. New fuel filter, new fuel reg, coil, new plugs, wires, air filter, oil n filter change. I thought maybe it was electrical, so i put my msd system in it, still had same issue.

    It run fine all winter, now that its warming up outside, it doin it again. It started back at it again last week. While tryin to figure it out, i accidentally touched the heater hose with my arm. It was so hot, i couldnt touch it, as was the upper rad hose. The rad cap n lower hose were both cold to the touch. Which lead me to believe the pump was bad and the truck was just gettin to hot n shutting down. Last sat i put in a new thermastat. Still cuts out, pops thru the intake, n dies. So yesterday i put a brand new water pump in it. Got it up to temp and the heater hoses arent as hot as they were, i can hold them in my hand. The upper hose is a bit warmer. The cap and the lower hose are still cold to the touch. While i had the pump off the truck, i used the water hose and rum water thru both directions thru the block and thru the heater core. The water run thru clear as it went in.

    After putting back together and lettin it get to operating temp to top of coolant, it idled a bit rough but came out of it when i gave it throttle. But once i started down the road, i could feel it kind of cut out, like a miss. A few minutes later, it started cuttin out and popping in the intake and died. It starts back up, but runs rough. Unhook the map sensor and itll idle high for a second n drop back to normal. If i put my finger over the line, it starts to die. When it dies, sometimes its like i shut the key off. Other times its like a stumble and die.

    So wat do yall think? Map sensor? Maybe need a new fuel pump again?

    Sent from my SM-A516V using Tapatalk
     
  2. Roush PSD Interceptor

    Roush PSD Interceptor 7.3L Straight Piped Diesel Staff Member

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    Welcome
    @indybama

    Fuel Pressure:
    35-45 psi on the fuel-pressure gauge with the key on/engine off, 27-37 psi with the engine running, 40-45 psi with engine running
    and vacuum hose disconnected from the fuel-pressure regulator, while at the same time being able to pump out 5.6 oz of fuel in 10 sec.
     
    Crazy Buy likes this.

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