Rough idle/start when engine is hot
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Rough idle/start when engine is hot
I just bought a 1996 F-150 4.9 I-6 4X4, 195,000 miles
new plugs, cap, rotor, wires, fuel filter just installed,
The problem I am having is when the truck has been running for some time and the engine is hot and you cut it off for 10 minutes and try to start it, the engine shakes violently at first (very rough idle) then if you just touch the gas pedal and give it some gas it settles down. On the highway it runs fine and it starts up great when it is cold.
My brother is a mechanic and said it might be the fuel pump or an injector has a piece of trash in it and when you turn the truck off gas is being pushed into the cylinder past the injector because the injector has some trash in it or is weak. He said when the engine is hot the fuel rail builds up more pressure inside then when the motor is cold due to heat comming off the engine and the fuel is vaporizing inside of the rail creating enough pressure to push the gas into the cylinder making that cylinder(s) flood.
If it's the fuel pump, why wouldn't it do it all of the time ?
Can anyone offer advice or your thoughts on the above or any new ideas on what would be causing this before I start spending $$.
Thanks so much !
new plugs, cap, rotor, wires, fuel filter just installed,
The problem I am having is when the truck has been running for some time and the engine is hot and you cut it off for 10 minutes and try to start it, the engine shakes violently at first (very rough idle) then if you just touch the gas pedal and give it some gas it settles down. On the highway it runs fine and it starts up great when it is cold.
My brother is a mechanic and said it might be the fuel pump or an injector has a piece of trash in it and when you turn the truck off gas is being pushed into the cylinder past the injector because the injector has some trash in it or is weak. He said when the engine is hot the fuel rail builds up more pressure inside then when the motor is cold due to heat comming off the engine and the fuel is vaporizing inside of the rail creating enough pressure to push the gas into the cylinder making that cylinder(s) flood.
If it's the fuel pump, why wouldn't it do it all of the time ?
Can anyone offer advice or your thoughts on the above or any new ideas on what would be causing this before I start spending $$.
Thanks so much !