Stop and Go traffic??

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#1
1996 Mercury Mystique 70,000 miles 4 cylinder. Starts and runs great, but sometimes stalls out at any speed. Always starts right back up after pulling over, but then may do it again 5 times in 5 miles. On the return trip, it may not happen even once. I'm thinking maybe fuel filter is plugging, but may be out to lunch ::) Where is the fuel filter on these ...and any other suggestions would be appreciated. Shouldn't a code get set for this kind of thing? I have a reader. Thanks!! RB
 
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#2
Does it sputter like it is running out of gas, or does it just die?..Does it do it more going up a hill or accelerating?....The in-line fuel filter is located downstream of the electric fuel pump module and is mounted on the fuel tank.........Jim


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jasonn20

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#3
Fuel filter is mounted on the gas tank.

Does your scanner have data screen where you can observe sensors?

I would try and get a fuel pressure gauge on here and see what your pressure is. This can be tricky since you have an intermitent problem. Just replacing a clogged fuel filter usually ends up that you will have to replace the pump as well. You should be able to change the pump by removing the back seat.

I would check all connections at the battery and for vaccum leaks.
 
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#4
Found in the records that the fuel filter was actually changed during a tune up earlier this year. My scanner only shows DTCs. When this is about to happen (the stall)...pressing the gas feels like it makes the car slow down...then it stalls within seconds. No sputtering...just stops dead. Sometimes, letting up on the gas pedal quickly will avoid the stall. It can happen anywhere...hills, level...but always during accelerating (vs. steady speed). Another thing, which may not be related as it has been doing this for quite some time...when driving about 10 MPH (like leaving a parking lot) often the car will surge (feels like the gas pedal is being pressed and release rapidly) while accelerating, until up to maybe 20 MPH...but this never causes stalling. Thanks for the answers so far!! RB
 
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#5
Have one of these in there?



They act up that way, think they call that erratic or intermittent operation. Darn things cost more than what the car is worth.
 
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#7
Certainly would check the wiring, connectors, and ignition switch first. What I normally do is hit it with a pulse, use a resistive load and run it my environmental chamber to make sure the module is not the problem.
 

jasonn20

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#8
I would suspect the fuel pump it needs 35-40psi to the injector rail any way of testing???

Did the problems start after the tune up was done??
 
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#9
Problem didn't start until about 4-5 months after the tune-up. Car was working like new...and still does...until this stalling and surging thing happens. Maybe I should invest in a fuel pressure gauge to rule the pump out (or identify it as the cause). Thanks all, so far!!
 
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#10
Have to test all that stuff out, son came home with a stumbling killing engine, he paid over four bucks a gallon for water in his fuel tank.
 
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#11
:( :( Took car to Ford but they too are struggling with this intermittent problem. They could see the oxygen sensor dropping off to zero volts (when accelerating?) and got a code for it (obviously one that I couldn't get)...but don't think that is what's causing it to suddenly stop dead. Would the fuel pump really do that, because if it was starving for fuel bad enough to stall, would it start up again instantly? There is also a sensor bad that increases idle when the power steering pump is working hard....but that's not the problem here either. Should I ask for a fuel pressure check? Any other thoughts? Thanks again!! RB :( :(
 
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#12
Found some TSB numbers that might relate, but can't find the specific info :'(. BCO824961010, BC9641961001, AND 98207.
 
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#13
Problem is getting worse. Car is starting to buck now at certain times...and getting code P1131. What to check or do first? Thanks! RB
 

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#14
You idle air control can cause you problems if it is not working well. I would still get a fuel pressure gauge on here and see what the pressure is when it is acting up. It look like a O2 lean condition code so it could still be a fuel pressure problem. I would check for any vacuum leaks as well if you have not done that already.