I have a 2006 ford freestar and out of the blue on the way to work it started to bog down ans stall out. Took it to three different shops and have learned nothing. I replaced the alternator, cleaned maf, and the basic stuff, also pcm is good and dry. When it cranks i can rev it up to good rpms only by pressing the gas slowly, if i push and "hammer down" on it it will start to diesel and when i let off it idols back to normal. Mechanic "said" he checked the fuel pressure and it was good, also no codes where picked up by three different people. Two mechanics have said its the security system seeing how when it starts to diesel the little light on the dash blinks and does the battery light. I just thought it did that because it was dieing. Then had a guy say it was the programed key going bad, (also does not make sense to me) but called a lock smith and he came and looked at it and said it was not it. Its like its not getting the gas air mix right and flooding out. Please help any ideas please.

 

It seems that the problem is with the fuel. The engine is not getting enough air fuel mix when it actually needs. I would suggest you to check the fuel injectors for proper functioning. Clean the fuel filters and also look for a fuel pump relay for proper functioning.

 

Sometimes the very simple and basic things evade us. Not knowing the maintenance history of your vehicle, if I may , when were the plugs and wires changed, and how many miles are on the vehicle ? As much as we wish they would run and last forever spark plugs get tired and so do the wires.
If there is any suspicion regarding the security system, you can always try the other key. That is a simple test. Sometimes keys get tired too. If the problem is with the PATS security system all it's functionality is contained in the vehicle's computer PCM.
The keys usually cause the most problems.

 

It is a 6 year old Freestar. It probably has 60 000 to 80 000 miles on it.

I would go with Hanky's suggestion and replace the plugs and wires and the coil pack as well. Coil packs can short out internally.

Also make sure that the alternator and battery are A-o.k. A bad Alternator can throw the ECM for a loop.

 

I have just replaced the plugs and man I really thought that was it, but was not. It did however help a great deal. Drove 30 miles and back with no problem, got in to drive again and it started the same thing. I can press the pedal slowly to a certain point and it stalls, starts, stalls, starts, and goes. Get on the interstate and can get down on the gas and it downshifts great and takes off. Ran it up to about 110 with no problems at all. But at lowspeeds it stalls only when gas pedal is pressed to certain point. Fixing to buy a scan tool :-( , but dont think its a computer issue. Please any other advice. Changed the fuel filter also.

 

Until you can get the tool to check it thoroughly something you could check in the meantime.
The EGR system may be isn't sealing as it should check for carbon build up problem.
The TPS may have a "flat spot" if the engine balks at the same throttle position each time.
Vacuum leaks cause strange things to happen.
Were you able to carefully check all the vacuum hoses and PCV hose for any possible cracks or leaks?
Don't forget to look for wear on the throttle body shaft and clean the butterfly.

 

Well found a vacuum leak at the air intake plenum bolts !!! Fixed it and then got all the way home from my dads and exit the off ramp and transmission goes to neutral and will not catch any gear, lol !!! Fix one problem and now another, any ideas ???

 

You could recheck all the areas you disturbed for a wire(s) that may have come loose or off. Since many functions are electrically controlled, including the trans, it might pay to check all the fuses. There could always be a separate trans problem.

 

Sounds like a camshaft position sensor or ignition coil pack. The CPS has a telltale chirping noise intermittently as its going bad. The coil will not be able to output enough energy occasionally causing the car to stumble or bog down.

 

Nevermind! Doh! I didn't see that you found the vacuum leak until after I posted. As for the tranny, unfortunately I don't believe the 06 was included in the recall.