07 expedition stalls out

[jlbabb21]

My car had a code pop up about vacuum leak and it stated that that the most common problem was the mass airflow sensor. So I changed it. Still having problems so I did some research and changed the throttle sensor. Still having problems. I have checked and checked for vacuum leaks and I have had other people help me look for leaks and can not find anything. It has been at the Ford dealership for almost 2 weeks now and they say there is nothing wrong with it and it is not throwing any codes. But there is something wrong with it. These are my symptoms. There are no codes showing. When I am driving down the road after a good 20-30 miles about 60-65 mph(we live way out of town, this is my routine daily drive), when I slow down to turn or stop and press accelerator it acts like it don't want to go. Like it is not getting any gas or something. When I let off the gas and press it again then it goes. The longer I drive it in a day the worse it gets and if I am pulling a trailer it is worse about stalling out(doesn't cut off, just not wanting to go at first). That is why I am hung up on vacuum leak but we cannot find anything. Has anyone else had this problem? A couple of years ago we changed fuel pump and the fuel filter has been changed recently too. Also, it eats coil packs like candy. Any help with that would be nice too.

 

[juan214]

Stop throwing parts at it. If you got a code for a vacumn leak and no one found anything clear the code see if it comes back.

• Year?
• Prior to the code did you change the air filter?
• Is it the only code you got?
• If the leak is not audible did you try spraying around the hoses, line, air intake assembly, and around the plenum?
• When you changed the Mass Air Flow Sensor did you clear the code?

Will follow up when I get back unless someone else jumps on.

 

[jlbabb21]

We have done everything we possibly can to find the leak and we come up with nothing. We cleared the code when we put in the mass airflow sensor and it's been about 2 months ago. No codes show back up and it still runs like I've described. Ford place can't find anything wrong with and we are just trying anything now bc I'm tired of going down the road and it not wanting to go after we stop or slow down. It's a 2007. Filters are good and we connected our scan tool to it when we sprayed hoses and it didn't show anything. We are stumped.

 

[juan214]

I don't believe the parts you replaced were the issue. Unless the MAF sensor was removed / replace before you got the codes. If it were and did not seal where the electrical comes out or the intake tubes did not seal. That's why I asked if the air filter was changed.

At this point I would start at the beginning. Starting with fuel pressure, check it a the rail. I know you change the pump already better to rule it out with tests.

Key on, engine off 240-310 kPa (35-45 psi)
Engine running 193-310 kPa (28-45 psi)

Low end weak pump may be going and or clogged filter. I know you change the filter. Usually they die @24 psi.

Just out of curiosity when you get to cruise speeds does it seem to float like the engine is off or a miss?

Check fuel pressure with a fuel pressure gauge the next time it stalls.

Has it ever stalled while idling or while driving after its warmed up?

Swap out the pump relay with another one in the box see if you still have the problem.

 

[jlbabb21]

The fuel pressure is good. It doesn't stall while idling only after I've been driving a while. When driving it does have a faint skip to it like the engine's not getting something.

 

[outdare]

The accelerator has a sensor and is drive by wire. You accelerator sensor could be going out or have a loose/dirty connection.

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[juan214]

The fuel pressure is good. It doesn't stall while idling only after I've been driving a while. When driving it does have a faint skip to it like the engine's not getting something.

• So after it warms up it will stall?
• Does it stall while driving and or after you drive then park and idle, or both?
• Seems like you lost everything in a sec without warning?
• Sometimes it will Idle then the RPMs drop then surge back up?
• Other times will just stall, then crank, and no start?
• Is there a wait before restarts?

 

[jlbabb21]

It doesn't completely shut off. After it warms up and been driving about 30 minutes or longer and I hit the brakes like to stop at stop sign or slow down to turn then press gas again it doesn't go. Car is still on and rolling but no acceleration then I let off gas and press again and it goes. RPM do not go up or down unusually. Sometimes after the car sits all night and I crank the next morning it is slow to crank but only split seconds slower. But it always cranks and doesn't stall while sitting there idling.

 

[juan214]

The accelerator has a sensor and is drive by wire. You accelerator sensor could be going out or have a loose/dirty connection.

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I would normally say look at spark next. I would start looking elsewhere now. Look at what Outdare suggested. I thought it may have been the Crankshaft Position Sensor systems sounds like the same symptoms. If you have a scan tool look at the Throttle Position Sensor reading and see if it's moving when you hit the gas or if there's a delay / Hesitation.