Stalling problem...Please help

jec1521

Jay
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OK guys, I've had this problem for a while now. Anytime I drive my truck for a long distance. Here is what I know:

1) stalls after an hour or so of driving, drives fine before that
2) Didn't happen once all winter and is now starting again
3) Started around the time that I deleted my EGR
4) my fuel pressure drops to less than 20 if it tries to stall at highway speeds. 5) Drops even lower (to about 5 or 6) if I'm idling or accelerating from a stop

So I'm assuming this is a vacuum issue, correct? A leak maybe? What's the best way to check for a leak? I tried spraying all of the vacuum lines with brake cleaner before but nothing happened. I also tried to spray down to the vacuum line behind the intake, but I'm not even sure I reached it.

Is there anything else that this could be?
 

jec1521

Jay
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Drop your tank bro. Your issue is in there.

I was told on the other site that it could be the fuel pump resistor. I took it off and tested the resistance of it and it came up 0. I believe this might be the problem. I bypassed the relay for now until I can get a new one.
 

02REDSVT

alienfreek
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Thats what I was gonna say Jay, most likely that resistor.... also replace your fuel pump relay while you're at it.... do this before you start tearing into the tank...
 

jec1521

Jay
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That's what I plan on doing, thanks for the help guys. What are the chances of this being a vacuum leak?
 

jec1521

Jay
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Update:

Had some more trouble with the truck this morning. After a while of driving, it stalled once, and the battery light came on. It stalled again later, and the battery light, SES light, and Engine coolant/Oil Pressure light all came on. I checked for DTC's with my Interceptor gauge, and nothing came up.

Any ideas?
 

87vertgt

Da Bears!
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my old stang did that exacpt same thing...was the relay.....



Jay.....your avatar creeps me out. change that chit.
 
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squirellracing

white lightning
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i had this problem it was that sensor they are talking about now as far as the lights and nothing came up just unplug the batt and see if they come back up or clear them one or the other
 

RIDE THE

Shake & Bake
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I was told its a FRPS...i have a 03 cobra that does that sometimes or did i should say, aint done it in awhile

Lightnings don't have Fuel Rail Pressure Sensors.

I'd also go with the resistor or pump assembly. I doubt that it could be a line or the Y in the tank. But, you never know. It could have a very small split in a line that would cause the low fuel pressure.
 

jec1521

Jay
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Lightnings don't have Fuel Rail Pressure Sensors.

I'd also go with the resistor or pump assembly. I doubt that it could be a line or the Y in the tank. But, you never know. It could have a very small split in a line that would cause the low fuel pressure.

The resistor is fine. Should I put in new pumps? Wouldn't both pumps need to be bad for the pressure to drop down to 5 psi or below intermittently?

What are the chances that this is a bad ground issue?
 

RIDE THE

Shake & Bake
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An intermittent lose ground might be the issue, but I doubt it.

All you need is an opening in the system after the pumps for fuel pressure to drop. Both pumps run at the same time. When you go into boost they get full voltage and they both operate at a higher speed which makes more fuel pressure.

IF, and I mean IF one of the hoses has a very slight split or bulge, or the Y fitting has a crack in it, the fuel pressure could drop because the pumps are just pumping the fuel back into the fuel tank instead of building pressure into the fuel lines.
 

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