2005 Grand Marquis fail at idle, bad ECM or fuel pump wiring?

Asked by Likwid Sep 18, 2019 at 10:33 AM about the 2005 Mercury Grand Marquis GS

Question type: Maintenance & Repair

Got a 2005 grand Marquis gs that fails if not
fed gas. Mechanic says it's either the ECM
or a wiring falt to the fuel pump. Car tries to
start, idles roughly for 1 second if fed gas,
but dies if no gas is given. Mechanic says it
could be bad wiring or the ECM, only a
master mechanic can tell for sure. I'm
wondering if I should wait a week for his
master mechanic or try to send it to a
reprogramming place, knowing the ECM
won't fix any fuel pump electrical issues?

1 Answer
5,415

Trippmeister answered 5 years ago

Fuel pump relays(s). They do go bad. easy fix, if that's it. Could be pump, if relays are good. Fuse, also. Make sure all the elec. works before spending all the money for a pump. Also, replace fuel filter, just in case. One relay on right side, one on left, under the hood.

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