ses light, car won't shift into overdrive,

[jorton]

1999 Mercury Tracer wagon

When the car is parked, uneven, popping pulses from tailpipe and the engine dies when I turn a/c on.

All of this started with the ses light last week. Per Advance Auto hand held tester shift solenoid C malfunction code P0760.

What I have done:
new sparkplugs
new fuel filter
new battery
Visually checked transmission wiring harnesses connectors and plugs for damage, corrosion. All were clean.
Checked timing belt for stripped teeth, and alignment marks on gears. All was good.
atf does not smell burned

I am saving a transmission pan drop for last. If anyone can make a connection between the misfire and the transmission problem, and possibly a solution that would be a great help. Thanks!

 

[JimPghPA]

I did a quick google search for "1999 Mercury P0760 code"

Fixya has a post that P0760 on a Ford of that era means that the computer has detected that the transmission shift solinoid is malfunctioning. So the question is what causes a shift solinoid to malfunction. I do not know the way that the solinoid works on that era of vehicle, but I would be looking to see if a vacuum line went to it. If so then if the vacuum system of the engine has a leak the solinoid would be receiving wrong information and then it would not shift at the correct time. In other words if the shift solinoid has an engine vacuum line going to it check for leaks somewhere in the engine vacuum system, including the line going to the shift solinoid, again only if it has a vacuum line going to it. And of course if every thing that tells the shift solinoid is in proper order, then look at the shift solinoid itself as possibly being bad.

Again, I am not familiar with that ear of Ford/Mercury/Lincon, and the shift solinoid may or may not use vacuum sensing, but it it does, an open (leaking) vacuum system can cause an engine to do strange things including run rough and stall.

 

[Colt45ws]

Well, the shift solenoid is the reason for no OD, but its electric so I see no reason for it to interfere with the operation of the engine unless it was locked on, which you would notice.

 

[punisher]

Usually means a problem with the solenoid, or the solenoid circuit. Break out the DVOM and find a pinout diagram of both the transmission connector, and the 104 pin connector at the PCM. See if the solenoid/circuit ohms out OK.

If by chance both of these problems started at the same time, and there are no other codes, it might be a good idea to first pull the PCM connector off and check for any water intrusion or corrosion.

I had a Contour mess with my head until I pulled the PCM connector to hook up a breakout box, and found a lot of corroded pins due to water intrusion.

 

[jorton]

I think the engine was the source of the misfire AND the transmission problem. The compression test this evening revealed an internal failure.

cyl 1 = 155
cyl 2 = 85
cyl 3 = 80
cyl 4 = 150

And the rest of the car looks as worn out as the engine is.

For sale 1999 Mercury Tracer
226,000 miles
compression bad

 

[Barkleymut]

ouch, that hurts. I always try to guess what the problem is as I'm going through the thread and didnt see this one coming. Hope you got plenty of miles out of her.

 

[Vikas]

any suggestion for miracle liquid? you have nothing to lose at this stage!

 

[Clevy]

Mos2. It plates metal. Should help the poor compression. Change the oil,add a can and report back

 

[jorton]

Originally Posted By: Barkleymut
ouch, that hurts. I always try to guess what the problem is as I'm going through the thread and didnt see this one coming. Hope you got plenty of miles out of her.


226,000 miles.

 

[zzyzzx]

Did you check for coolant in your oil and oil in your coolant?