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EricFromCT, Ford Lincoln Mercury Senior Master
Category: Mercury
Satisfied Customers: 3958
Experience:  ASE, Ford Lincoln Mercury Senior Master, Diesel, Kia Professional Elite
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2007 Mercury Montego Premier. Began to stall while driving.

Customer Question

Hi- 2007 Mercury Montego Premier.
Began to stall while driving. Antitheft light and battery sensor came out as car cut off.
Dealer told me throttle body was bad. They replaced it 2x. Dealer refuses to take car back. Ford being incredibly unhelpful. Car still will not consistently drive without jumping(as if its going to stall) and antitheft light comes on when it does this.
Brand new throttle body, water pump, engine coil. Car has 91K miles.
Got code P2107 last week. Believe it is a short circuit or similar electrical issue between PCM and throttle body.
Any guidance would be REALLY appreciated.
Submitted: 1 year ago.
Category: Mercury
Customer: replied 1 year ago.
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Customer: replied 1 year ago.
This happens with all keys i use. Am under the impression it is not actually antitheft system but rather an electrical issue somewhere.
Dont even know where to start. Really need my car running. Battery has been unplugged for an entire day to try and fix this.
Ford claim that they reprogrammed PCM when putting in throttle body but I'm not sure.
I don't believe throttle body was ever actually bad, but rather was some sort of electrical issue that threw throttle body codes.
Expert:  EricFromCT replied 1 year ago.

Hi. I have seen throttle body codes repeated before. There is a common spot for wires to chaff. On the passenger side in the rear near the firewall, there is an ac line that runs near the wire harness. A lot of times the harness chaffs on the ac line and causes the code and the vehicle to go into a low power mode. Can you check that area? You may have to grab the harness and flip it around to see the back side. Can you check that and let me know?

Customer: replied 1 year ago.
Id love to but i need little more information- Im not an expert and don't 100% know exactly where everything is.
The harness is the part that plugs into the throttle body actuator yes?
So you want me to check the wiring where exactly?Thank you for the response!
Customer: replied 1 year ago.
Do you mean back behind the steering fluid container?
Customer: replied 1 year ago.
This is what I'm looking at under the hood-
Expert:  EricFromCT replied 1 year ago.

Yes exactly. Behind the power steering res you will see an ac line that runs near an electrical harness. This area should be checked.

Customer: replied 1 year ago.
Went back there and everything seems to be in order. But again I'm no expert.
Car is having trouble starting now.
Had it started this morning and it shut off while idling in park.
Could loss of electricity be causing that and where else could it be happening?
The battery is good, tested with multimeter.Thank you!
Customer: replied 1 year ago.
This is what it sounds like
Expert:  EricFromCT replied 1 year ago.

Loss of electricity probably will not cause this. You can check the battery voltage with a voltmeter when it is running to check the charging system. Should be over 13 volts.

Customer: replied 1 year ago.
the stalling and trouble starting are likely related, but not related to loss of electricity?
Chaffed wire somewhere along the wiring harness is more likely?
Thanks again.
Expert:  EricFromCT replied 1 year ago.

WHen you have p2107 the vehicle is going to be in a failsafe mode. It really does act like a throttle body concern. I understand the dealer replaced 2 already. I have seen this issue at the dealer before and it was a chaffed wire setting the p2107. If the throttle body does not get rid of the code, then wiring is likely. The harness I want you to inspect is not super easy to get your hand on? So did you grab the harness, twist it around and check the wires where it comes in close contact to the ac line?

Customer: replied 1 year ago.
I thought i did but try and walk me through that little bit more please-
Big and wrapped in black electrical tape is what i thought i was grasping, but how is it in contact with AC line? Just happens to touch the AC or it is firmly held in place against the AC line?
Thanks again!
Expert:  EricFromCT replied 1 year ago.

Its not the same on all the montegos. SOme of the cars the line is not even touching the line. Others the harness is resting on it. I know that is a common spot to get throttle body codes. I have repaired many at the dealer, AFTER replacing the throttle body. You may need to actually remove some of the harness hold down clips or nuts if you need to flip it around to chek the wiring.

Customer: replied 1 year ago.
The engine will not even turn over anymore.