engine problems on 1995 Mercury Tracer

what makes chugging on acceleration, I also get very poor gas mileage

Asked by for the 1995 Mercury Tracer
Do you have a check engine light on?

I would suspect an air intake leak (check the hose after your air filter box to the intake - is it cracked and leaking perhaps? Check closely...fairly common on this car), a vacuum leak, something like that. You could also have a fuel pressure concern - after checking for obvious leaks, have a fuel pressure check done.
There is no check engine light on, It chugs for a bit then all of a sudden it will get up and go
I lean towards checking fuel pressure. But you still could have the air leak.
Wher is the maf sensor located?
The MAF sensor is the sensor on the air tube after the air filter box.

You really should not replace this part frivolously - make sure you check for the barometric pressure reading and for fuel trim codes. Otherwise, it's probably ok.
o2 sensor