My '90 LSC (96,000 miles) has just starting stalling while I am travelling at 30 to 50 MPH. While I am still rolling I shift into neutral, turn the ignition switch to off and then start and it starts right up. I have been suspecting the fuel pump because I have been hearing an intermittent humming noise from the pump.

Does this sound like a pump problem or something else.

Thanks

Could be... or to stretch the possibilities out a little bit, an intermittent short to the pump. A good time to replace the fuel filter too.

My '90 LSC (96,000 miles) has just starting stalling while I am travelling at 30 to 50 MPH. While I am still rolling I shift into neutral, turn the ignition switch to off and then start and it starts right up. I have been suspecting the fuel pump because I have been hearing an intermittent humming noise from the pump.

Does this sound like a pump problem or something else.

Thanks

theres always a humming sound coming from the pump, kinda a good way to know if it ever goes out on you. i would do a fuel injection service on the car, replace said fuel filter, and see what happens. if it persist to do it again then replace the pump. but thats me.

My '90 LSC (96,000 miles) has just starting stalling while I am travelling at 30 to 50 MPH. While I am still rolling I shift into neutral, turn the ignition switch to off and then start and it starts right up. I have been suspecting the fuel pump because I have been hearing an intermittent humming noise from the pump.

Does this sound like a pump problem or something else.

Thanks

Fljackson,
Might just want to check the ignition switch to see if there is a short.

...
Does this sound like a pump problem or something else.

Thanks

You are welcome and yes it does.

Test your fuel pressure at the rail. The proceedure is listed in the forum.

Before 100,000 miles, replace your PCV valve and Oxygen sensors. Ignition switches normally don't fail on 1990 - 1992 Fords as they were redesigned and relocated in 1990. Any and all factory ignition switches for Lincoln Mark VIIs that were installed BEFORE 1990, should be replaced.

fljackson,
Let us know what you test and what your findings are and what you replace and what those findings are.

I have replaced the fuel filter and pump and the stalling problem persists. I have been driving the vehicle and it seems to be getting worse it now takes six or seven attempts to start it after a stallout.

Any other recommendations would be appreciated.

Thanks.

I have replaced the fuel filter and pump and the stalling problem persists. I have been driving the vehicle and it seems to be getting worse it now takes six or seven attempts to start it after a stallout.

Any other recommendations would be appreciated.

Thanks.

Pull codes. OBDI (AutoXray) scanners are cheap now.

When you replaced the pump, did you reuse the existing sock or install a new one?

Test your fuel pressure at the rail. The proceedure is listed in the forum.

Before 100,000 miles, replace your PCV valve and Oxygen sensors.

When I replaced the pump I replaced the sock as well. The fuel pressure is fine.

I do not have a "check engine" light that comes on. That being the case will the scanner still be able to determine anything?

Thanks.

When I replaced the pump I replaced the sock as well.
Aftermarket socks require a minimum of 1/2 tank full of fuel to operate or they start sucking air and you stall during accelleration, even though you KNOW you have a half tank of fuel.
The fuel pressure is fine.
What did the pressure gauge read?
5#?
25#?
50#?
I do not have a "check engine" light that comes on.
That in itself is a problem.
Replace the bulb.
Diagnose.
Repair.
That being the case will the scanner still be able to determine anything?
I don't think so.
The CEL is a part of the diagnostic circut, just like the bulb for your alternator.
Thanks.
Don't thank us until you've completed ALL of the diagnostics and found and corrected the problem(s).

The fuel pressure was 50#.

The check engine light works, it just isn't on when it is running.

This is pointing more towards a corroded/broken wire (in the insulation, intermittent connection) or possibly a loose ground? Having moved the wires around and the pump is cutting out more, possibly the issue lies at the tank?

Three things come to mind other than the things already mentioned.

First: Fuel pump relay. Check connector for corrosion, or loose. Replace relay with known working unit. Test drive.

Second: Intermittant impact switch in trunk. Bypass switch and test drive.

Third: I have seen TFI's act like this. Perhaps the intermittant sound is not really intermittant.
Art

The fuel pressure was 50#.

The check engine light works, it just isn't on when it is running.

Try a new fuel guage.

Scan for codes.

I set out to replace the TFI and while I had the distributor out of the engine I replaced the pickup module as well.

The engine runs great and doesn't stall any more.

Thank You to all that responded and offered suggestions.

...
Thank You to all that responded and offered suggestions.
You're welcome.

Thank YOU for maintaining and preserving another Lincoln Mark VII!