My 2002 Mercury Sables gives a "bucking" sensation once I am at a steady speed/ overdrive 50+ mph. It was running fine, no skipping or bucking. I shut it off, went into work, left work to go home and suddenly have this problem. The sensation is similar to trying to drive a manual transmission in 4th gear at a slow speed.

Marvin

• 85242 Answers
• Posted on Sep 04, 2008

SOURCE: overdrive transmission

you have an issue with the torque converter clutch, your symptoms indicate this is the issue, possible TCC solenoid problem or the torque converter itself has a shorted magnetic clutch.

SOURCE: 1989 Mercury Topaz Transmission problem !!!

overdrive should be activated by a solenoid ..internal and perhaps an external one also.. in 89 the computer was primitive and i dont think controlled shift points..also if engine health is bad or missing or vacuum to any cacuum modulator at trans is damaged or compromised.. these issues could occur...good luck

SOURCE: Transmission hesitates shifting into second and perhaps third gear when driving slow. When acceleration is positive transmission shifts smoothly. Reference "99 Mercury Transmission" as Subject when

Several things could be causing your problem:

1. Auto transmission fluid is low
2. Auto transmission fluid needs changing; this is an area that gets neglected by a lot of people;check the fluid and if its brown or gives off a burning smell, it needs changing. Very old transmission fluid will cause slipping in the transmission; if this is the case, it should be changed along with the filter

Jeffery Lewis

• 329 Answers
• Posted on Jun 06, 2009

SOURCE: P1401 still after replacing EGR pressure and EGR valve

Yes that is what is wrong the intake manifold is plugged with carbon restricting EGR flow you need to clean out the ports to correct the problem if you run the car to long you will burn the DPFE ( the EGR pressure sensor ) out agian

Marvin

• 85242 Answers
• Posted on Nov 04, 2011

SOURCE: What could be wrong with Transmission?

Hello
1st let me explain how the transmission in this car is shifted, there is a computer control module, it is called the "Powertrain Control Module" or PCM, some cars have a separate computer that is just for the transmission, this is a TCM, your cars PCM does both jobs of running the engine and shifting the transmission. The actual shifting is done by electric solenoids inside the transmission which the PCM controls by grounding them, when the computer determines it is time to shift based on vehicle speed and transmission fluid temperature and other inputs from the engine sensors it grounds the proper solenoid that shifts the transmission up or down to the appropriate gear, it monitores the shift electronically and if it doesn't see that the transmission has done what it was commanded to do it sets a fault code in its memory. I have read your problem and no mention is made that "Your Mechanic" scanned the system for fault codes, if he did and nothing shows up then you have a mechanical fault in the transmission and it will need to be torn down and rebuilt to correct this shift problem.
My experience is 25 years as a Ford factory trained repair and diagnosis technican.