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rpmdiag, Tech and Instructor
Category: Ford
Satisfied Customers: 6721
Experience:  Since 1975
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87 ford f150 4.9 liter straight six, misfires. all six plugs

Customer Question

87 ford f150 4.9 liter straight six, misfires. all six plugs has heavy black carbon on plugs, trying to diagnose problem
JA: How many miles are on the car? Is it a steady misfire? Or random?
Customer: 104K, steady, replaced MAP sensor, new plugs, wires distributor cap/rotor. Drop gas and put in new.
JA: Are you fixing your F150 yourself? What have you tried so far?
Customer: fixing myself, replaced MAP sensor, plugs, wires, distributor cap/rotor. emptied fuel tank and put in fresh.
JA: Anything else you want the mechanic to know before I connect you?
Customer: no visible moisture in the oil crankcase.
Submitted: 9 days ago.
Category: Ford
Expert:  rpmdiag replied 9 days ago.

Hi, I'm Ron and I will be helping you today.
Stand by for a moment while I prepare your answer.

Expert:  rpmdiag replied 9 days ago.

The fuel pressure regulator will cause this due to no vacuum going to it or the diaphragm is ruptured.

Thanks, Ron

Customer: replied 9 days ago.
I get the part and see what happens, thanks. Mark
Expert:  rpmdiag replied 9 days ago.

You're welcome Mark, thank you too and please remember to rate me 5 stars and keep this link in case you need me again later on.

I don't get credit for helping you until you rate me:)


Customer: replied 9 days ago.
Ron, can you provide a pic on the location of the FPR? Been trying to search on web and pics are no longer available.1987 Ford F150, 4.9L, straight six.Mark
Expert:  rpmdiag replied 8 days ago.

I don't have a pic of it, but it is located right on the fuel railin the back. There is a vacuum hose going to it too.

You can't miss it.

Thanks again fora great rating:)


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