Automotive Forums

i have a 1998 mercury sable with a AN4X trans. when i am driving on the highway it doesn't want to stay in 3ed (overdrive) it will jump up to about 4000 rpm from about 2650 rpm. but if i let off the gas it will shift back down. to much gas will make it shift agin. i have replaced the filter and fluid. the computer says that the performance solenoid is stuck off or bad. or the trans. if falty. the only thing i can thank of is to replace the hole trans. bout that is going to cost $900 from Auto Zone with a warinty      

sounds to me like the TCC solenoid  the coverter clutch , or the EPC solenoid needs replaced,do you have any codes?  

yes i do have the codes they are P1744, P0136, P0141, P1401, P0761...

now the car wont start i replaced the spark plugs and wires... it sounds like its not getting enough gas so i also replaced the fuel filter. but it still don't run... if i plug the intake about 90% it will run. i tried putting my finger over the MAS (mass airflow sensor) it stared to act up so i figuring its not the MAS. i am stumped....  

1744-EPC solenoid circuit.  
0136-OX. sensor bank 1 sensor 1
0141-OX  sensor bank 1 sensor 2
0761 Shift solenoid "c" stuck off.
I have seen oxygen sensors create havic with the shift on electronic shift trans.I would chang the OX sensors first, easier to change that the EPC and Shift solenoid. The EPC and shift solenoid are in the side pan of the trans.Not much room to work with.  

P0761 Shift Solenoid C Performance or Stuck Off
P1744 Torque Converter Clutch System Stuck in Off Position
    Bothe of these are transmission related you can find out if you can change them yourself.
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P0136 O2 Sensor malfunction
P0141 O2 heater malfunction
 and this is most interesting
P1401 Differential Pressure Feedback Sensor Low Circuit
  This is actually the EGR System --Ford gives it another name

A car will run with out an O2 sensor- its computer will open on whats called open loop mode.
But if the EGR valve is stuck completely open it will flood cylinders with exhaust gas as soon as yu turn the engine over. The car will pop a liitle in the beginning and then since its flooded with smoke on the intake stroke it will want to die down. It this the situation??
If it is then you should first try cleaning the egr parts because they may br jammed up with soot.Or you may have pulled a wire connection with all that invetigating,,or a vacuum hose may be loose or not tightly connected. But this is where I'd start my search.
Are you testing things?? or just changeing parts.  

I am assuming that you have some sort of automotive repair manual for this model and year car. Either a Haynes [my choice] Chilton, or maybe a Mitchell [more expensive but much more detailed]
Mercury is a Ford product and they like to use different version of the same part in any model's year.
I've had some older manuals for earlier model years and as a for instance they had 3 different versions of the EGRSystem for just one model year.

Another thing is that 1998 was still new for the OBD11 trouble codes and they were still tweaking and refining it. Thier cars computers were not up to analyzing all of the codes they put on thier lists.

If you have a book check how many thermostats are on the engine. Some have two. One for the dashboard to tell the operator  and another that was hooed to the computer and controls the 'choke' when its hot or cold,,but not the operator. If most of your trouble is on start up it may be defective telling the computer the engine is hot and not dumping enough gas into the engine,,,,hence the reason why you can get it to run when you starve it for air.  

I have a 99 Sable.  The check engine light comes on only after an hour of highway driving, then goes away when back in the city.  Ford said it is code P1744--torque converter sticking--and that I have to replace the transmission.  I'm skeptical.  Transmission seems to work fine.  Fluid is fine.  A second mechanic told me it could just as easily be the computer notification system.  Any suggestions>  

The 99 Sable poster really should re-post this problem as a separate item ans not get into the 98 owners problem. This will get everyone confused  as to who we are talking about.
When the 99 guy re posts he/she should be a little more specific about the problem.
Like is there any difficulty driving the car.
Are you aware that the torque converter is locked into position by a solenoid? and just that part alone is replaceable with out having o replace an entire transmission.
That being the case we would like to know more about your Ford dealer and what his remarks were when he suggest replacing an entire transmission.  

Sorry for the late reply on this post but I hope you didn't listen to everyone going on about repairing the trans on this car.  I noticed you had several drivability codes, like the P0136.  Keep in mind on these codes the P stands for Powertrain and your P01.. are for the engine and the P07.. or P17.. codes are for the trans.  Always, always ALWAYS repair your drivability problems before trying to fix a trans.