1993 Mercury Sable has ran fine till last month. When you are out on highway is jerks and lugs. Does it mostly when at steady speed notalways when you accellerate but sometimes. Whole car actually shakes when you get up to very high speed of about 70.


Please help this is my teenagers car and he nor i can afford to buy new one or spend a lot of money on this one.


Thanks in advance.

sounds to me like you should change the fuel filter. how does it idle? has the car been run out of gas lately? did the car ever shake before?

Not really occassionally in town it would do it. It has started it more constant within the last month. It seems to idle fine and it has not been run out of gas to my knowledge but will check with my son.


Thanks

could the shaking at high speeds be caused by unbalanced tires? not sure what you mean by jerking and lugging. if you let go of the steering wheel while going in a straight line will it stay in a straight line?

No it is not the tires. They were just rotated and balanced. You can feel that it is within the motor or drivetrain. It is like yourbeing towed but hitting the end of the chain and jerking the car. If youknow what I mean. Edited by: rdoss30

sounds like the car is missing at times is it more noticable when wet out were the cap rotor and wires ever changed try spraying the wires with a water bottle with a light spray and see if the car starts to run rough let me know hope this helps also is this a 3.0 or 3.8 eng?

your question is still on my mind. does it feel like it's being put into gear while the rpms are up? have you checked the tranny fluid? if so does it smell burnt or have darker red color than normal? let me know if you've had any progress or figured out the problem.

I had a car that did that also when at a higher speed and as long as you hold the pedal steady it would jerk like you said. The only way I could stop that was by pressing and releasing on the pedal and you wouldn't have that problem.
What did solve the problem, mind you it only worked for 3 months, was I changed the O2 sensor and it ran beautifully during those 3 months.
On Hindsight, I would say there is something wrong with the exhaust system, maybe it was plugged up (at the cat converter or muffler) at the time and that's why it only lasted as long as it did.

1-Radiator...if your car is out of water it will do that.

2-Low Gear (low RPM) in case of climbing a hill or something, that case gear will not shift to lower gear and car will rattle.