Hey guys new to the form.

Hope you guys can help me out here.

Have a 2003 Ford Taurus SE with the 3.0 Vulcan.

Brake booster died on me Pumping air out the pedal side so I replaced that and the master cylinder.

Now the damn thing dies at idle. No codes. Search the net for days finally decided to replace the IAC got a good price 42 bucks no go. Rackin my brain no idea where to go from here so I Unplugged the MAF sensor, the car died Immediately. So I thought what the hell I'll unplug the throttle position sensor. Ran fine no stall issue but the throttle response was lacking severely. Thought a new throttle position sensor would save the day but of course not. Don't have tools to check voltage pressures or anything like that so I'm kind of stuck. Any thoughts you could help point me in the right direction would surely be appreciated!

 

Lot of things can produce a stall at idle. What is needed is a look at the data stream info to see just what is happening or not happening.

The good ole days of the usual items causing a problem are gone and plenty of new things have been added,
Guessing can get expensive and disappointing and a scan tool would help a lot by providing running data that can be observed.and examined.
Of course, we need to know what we are looking at too !
We do need to be careful with parts these days. Good price does not necessarily mean good quality. Sometimes results in replacing one malfunctioning part with another.

 

Thanks Hanky. I'm trying not to throw parts at it but, without the proper tools it makes life rough! Both purchased parts are genuine Motocraft! I only have the one car and I need to keep it running to get back-and-forth to work so this is really a bummer. Yeah i did spend $110 on the blue driver scanner hopefully that'll help with live stream data. Found a killer deal on a fuel pump Motorcraft of course 120 bucks but, it will take the last little bit of money I have.. Gotta make this decision on the pump very soon or I lose the deal. Yeah I don't know what to do at this point this is so frustrating. Thank you for the input though. Was hoping maybe somebody could give me a definitive answer on the subject but, with the millions of different possibilities causing stalling I'm not even sure if I can fix this. I'm no mechanic but, I have a lot of experience working on cars..
Anyway thanks again for the input I'll keep plugging Away at it.

 

Quaalude,
I have some reservations of the fuel pump being the cause of the problem.

If the vehicle performs well all other times , I doubt it it is starving for fuel.

By disconnecting components while the engine is operating will cause trouble codes to set in the vehicle's computer. This can produce false info and get us on a wild goose chase.
Don't know what was checked and if stalling is the only problem at this time and it still allows the vehicle to be used,we might be able to come up with some checks that might shed some light on the actual cause. What do you think?

Was the problem present before the booster was replaced?
I have something for you to check. It is the curved piece of hose that is part of the PCV system. Those hoses would crack and allow addl air into the system and could produce a stalling problem.. Look it over carefully and replace it if necessary, and let us know how you make out OK, thanks.

 

Car ran fine before the booster M/C replacement.

Checked for vaccum leaks...none. Physically manipulatived wiring harnesses, wiring and connections. No change. Replaced PVC elbow. Was cracked again but, no leaks. Strange just replacing the 2 parts a stall condition with no codes would follow?

Since it only stalls hot. Would I be correct in assuming this to be electrical? My train of thought is a resistor, capacitor or potentiometer. Once the component heats up a short ensues.... But, why intermittent?

Hopefully the scan took shows up soon...

On a side note. Year or so back AC pump sized up. Rerouted belt to eliminate the AC. Can't afford a new pump. Electrical connection still hooked up just doesn't run the unit. Ran fine. You think maybe the computer doesn't see a load so strange things happening now?

Was out of work for half a year new knees. Struggling to survive right now.

Thanks so much for the help Hanky....

 

My first suggestion because it has happened before.
If the PCV elbow is cracked, replace it.
I do not believe the A/C belt being off should cause a stalling problem.
When the air is turned on the ECM jacks up the RPM in anticipation of an impending load.
If you have the engine idling parked in place and in neutral or park will the engine stall then? yes/no
I ask this because if the converter clutch is not disengaging when coming to a stop, it will stall the engine.
After the engine stalls , does it restart easily?
When the engine reaches what is called operating temp the fuel system goes into closed loop and the computer with the help of the oxygen sensor(s) adjusts fuel injector on time accordingly.. Do you know if the scan tool you ordered will provide data stream info?

Since you were in the area while working, did any vacuum lines get cracked but did not come off? Did you try removing the vacuum line from the engine to the booster and examine it for any damage?

 

By any chance is the one way check valve on the new booster at fault??