Need to change the fuel filter in a 86 ford tempo

stop guessing as to what is next to waste money on
have the fault codes read and fix what shows up

In the gas tank.

Likely a fuel delivery or fuel contamination issue (lots of these lately, for some reason).
Start by changing the fuel filter, then proceed to check for proper pressure at the fuel rail. Check the operation of the fuel pressure regulator, the fuel pump, and the fuel pickup strainer. If fuel delivery is good, and spark is good, suspect contaminated fuel.

i think u can just undo gas cap an that will work

PUt a bucket under the filter . Have plenty of rags ready. Depressurizer fuel system by depressuring fuel rail schrater valve and placing a rag over it.
use a racket and socket and wrench to remove banjo bolt.Once bolt is cracked open remove it and hose from filter . Remove filter from bracket.

Installation is reverse remember to use fuel o rings.

you may need to change you fuel filters and your air filters

change to a good Motorcraft (Ford) oil filter with good check valve in it.

Try adding some Chevron Techron Fuel injector cleaner with less than 1/4 tank of fuel. It will clean varnish from injectors.

This applies for fuel injection and carb. follow the acceleration cable to the carb/fuel injection, the cable is aroun a wheel look a like mechanism, there this wheel there schould be screw that pushes the acceleration open... please let me know so that I can Assist Why is the idling to slow, does the car Miss fire?

Check under driver seat area near frame for filter.

If you don't depressurize the system you will get sprayed with fuel.