Black smoke

Some of the causes of black smoke would be the fuel pressure regulator and the mass air flow sensor. More likely the sensor than the regulator. Also, when mass air flow sensors go out of calibration, they do not always generate a trouble code.

Just a few quick ideas.

There are a lot of possibilities here. Bad signals from the MAF can "confuse" the computer, causing many possible "reactions." The computer decides which gear to activate in the transmission based on inputs from sensors. It calculates for engine loading, RPMs, road speed, etc. If a sensor gives a reading that is not correct, but not out of range, it can cause the computer to select the wrong gear. This can give the impression of slipping. If the computer selects a higher gear than it should, it can seem very sluggish, like if you put a manual transmission in high gear at 5mpn. If this happens with an automatic, the torque converter is then the only reduction available, so it will rev up to stall speed without making the car move as it should.

There is also the possibility that you have more than one problem, in which case the two symptoms may be unrelated.

Start with the problem that is the most important, and then work from there to see if other problems exist.

As with any diagnosis, do not overlook the basic needs of an engine - fuel/air mix, spark, and compression. If one goes wrong, the other two will not matter. Too many people start out by guessing and changing parts. This is an expensive way to effect a repair.

A live reading from several sensors and a fuel pressure gauge while it is acting up would be a big help. If you have a scan tool with this capability or a friend that has one, that would be a good place to start. Good luck.

Hello, I'm Danny.
If you want to check codes for an OBD1 system here is the tutorial:

https://www.2carpros.com/articles/ford-lincoln-mercury-obd1-1995-and-earlier-diagnostic-trouble-code-definition-and-retrieval

After reading, scroll the page to find Ford.Hope this helps and thanks for using 2CarPros.

Hello again,

Is the check engine light on ? Here is a tutorial for black smoke:

https://www.2carpros.com/articles/engine-black-smoke

Hope this helps and thanks again for using 2CarPros.

Hello again.

I do know that auto parts store AutoZone will check your codes for free. When you get the codes- get back to us with the code number and we can then help you properly diagnose the issue. Thanks again for using 2CarPros.

Is the check engine light on? This happens when cold? Or all the time, even after re starting a hot engine?

First step is to read the codes, Autozone does it free, then post codes found here.
Or try to read the codes yourself: Jump the two termnals shown together and turn key to "ON" and count the flashes... a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 11 or 111. Write them down and post here. First do this with the key on engine off, then again with it running.

Things to look at, O2 sensor VERY important, Coolant temp sensor, this acts kind of like a choke for fuel injected cars. Black smoke = too rich, too much fuel.
With 200,000 plus miles I would replace both! After parts replacement remove the negative battery cable for 5 minutes to clear the KAM(keep alive memory) or the computer may not know the new parts are there.

Changing the fluid shouldn't have caused this problem, im wondering if you may have bumped or pulled a wiring harness by the dipstick, sounds like iac, check the wiring and let us know, check everything close to where you were working up top

jim

Pull the code/s from the computer-black smoke could be the oxygen sensor/s not adjusting fuel demand. Excessive fuel pressure due to pressure regulator/MAF sensor.