95 mercury sable 3.8 liter was missing bucking etc when I drive above 6o its worse however if I put it in passing gear the problem disappears . The shop changed fuel pump assembly sending unit etc fuel filter , new plugs wires etc. also replaced the motor mounts had rusted been damaged and broken or worn out, still does it now not as bad help!! desperate need to start a new Job monday , dont wanna break down

Has anyone checked the converter? Has only tried to check those problems rather than just replacing parts?

well we have paperwork showing a new converter I assume u mean in the exhaust and not a torque. We did check the fuel pum it did have to be replaced and the filter was old 161 thousand miles on it, and motor mounts had to be replaced so we know those are fixed they checked the plugs and wires

He means the torque converter. The transmission shouldn’t need a rebuild to fix the lockup mechanism. If it does, you need a different car. Yours isn’t worth the work that you have already done added to a rebuild. You were ripped off by “half a job of diagnosis”. Half a job is done by untrained or inexperienced mechanics.

well its not a transmission problem it was checked , it even misses when its idling I agree that the people who did the aforementioned items were less than knowledgeable , but those parts were pad I saw them before and after

To clarify, does it now, misfire, or buck, at any speed or at certain speeds? Does it misfire, or buck, during acceleration? Or, is it just noticeable at idle?
Did they change the distributor cap and rotor?
With the problem at idle/ low speed, it’s not in the A/T torque converter lock-up.
The problem is, likely, in spark. It could be in the ignition control module…especially, if it has the TFI module.

all speeds more at 45 during acceleration if i do a fast acceleration , it is lessened it has a coil i believe and distributor neither were changed. I am going to drive it on a small trip today to oak hill from mullens about 30 miles one way so we will see how it does it does not buck so much as just feel like it looses spark for a brief second not really quitting Thank you so much for your help

It’s difficult to determine, without doing certain tests, if the problem is caused by spark, or fuel control. The fuel injectors may not have good spray patterns. Deposits in the fuel injector(s) can cause a poor fuel spray pattern. The poor spray pattern can cause misfire. To help remove any deposits, get a can of Techron, or Sea Foam Cleaner, from the auto parts store and pour it into the gas tank. Then, as the fuel is used, it will clean the fuel injectors. Of course, all gasoline sold in the U.S.A. is required to have fuel injector cleaner; but, they may need additional cleaning.
Are you using the recommended octane gasoline? Even if you are, try a tank of the next higher octane. Deposits in the engine can cause a need for higher octane.
If the ignition timing is adjustable on your engine, it needs to be checked. Improper timing can cause misfiring…especially, during acceleration.

ok well it sounds like a bup bup bup bup bup when driving this am was a little difficult to start saw the distributor and a black box next to it doesn’t look like a coil