1996 ranger 4.0 codes po171 and po174 come up on the screen

all misfires and bad mixture of fuel and air

https://www.google.com/search?q=05+TAURUS+CODE+SHOWING+po171+po174+po300+pO303+pO304

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You have to component test to find a problem

Only failed parts get replaced

Codes have nothing to do with parts

You can have codes & not need parts

Codes only indicate an out of range condition

You have to find out why

All OBD Codes are on the internet with
print,charts,video,solutions

You Type your codes & read up

Study OBD 2 Systems also

OBD PO171
OBD PO174

I had to Google Cen Tech as i never heard of it

They appear to be inexpensive low end for sure

You won't get a lot of data out it

If your never planning on going to professional software,
consider the top scan/code reader type tools like Innova Professional or at least mid level Actron & a couple other brands

You really need to see sensors,emission monitors, so
your ready for inspection

You will only get Generic Codes from a code reader
not body functions likes abs,air conditioning,srs,& others

More data is better-- you will learn these systems as time goes by

They have been with us for 35 years now

OBD1 15 years
OBD2 20 years

Lean bank 1 and bank 2 , and throttle actuator system fault. Check reason for lean codes 1st, vacuum leak(s), air inlet boot and hoses, or low fuel pressure / clogged filter. Repair as needed then clear codes and recheck .

https://www.obd-codes.com/p0171

May be of help tracing the route of the prob

Description : The adaptive fuel Strategy continuously monitors fuel delivery hardware. The test fails when the adaptive fuel tables reach a rich calibrated limit. Now that we have an Idea of what the codes mean , we need to narrow them down. More than likely the problem is causing both codes to set. Keeping this in mind, lets concentrate on Code PO1309. Of the possible causes listed above I see two Sensors that may throw up a lean code. I would look at the MAF Sensor first and then the Temp Sensor. You may find that if you remove the internal Sensor from the MAF Case that some degree has collected on the thin wire. If you find debree, use a Q-Tip to clean it. DO NOT USE CHEMICALS TO CLEAN IT. If no debree is found, try a Known Good MAF Sensor. Still no fix, move on to testing the rest of the Sensors on the list till you find the problem. Keep in mind that the check engine light will have to be cleared after you have fixed the problem.

This can be caused by a faulty mass air flow sensor

LEAN CODES, CHECK FOR A VACUUM LEAK AT THE INTAKE MANIFOLD GASKETS, USE A CAN OF CARB SPRAY, WHEN U HIT A LEAK THE ENG WILL CHANGE TONE AND RPM.

your computer is reporting bank 1 and 2 too lean, usually caused by the mass air flow (MAF) sensor, you can usually clean this sensor and reset the light. Clean it with electric cleaner or brake cleaner, make sure it is dry before reinstalling, also take care not to damage it. Hope this helps, let me know