Yes, it should set a code if MAF is unplugged
Not what you are after, you want to see what fuel trims do without the MAF

 

this is what I got with it disconnected after warm up

ABSLT TPS 19.2%
ENG SPEED 697rpm
MAF 0
COOLANT 183 degree
IAT -40
ST FTRM1 -5.5%
LT FTRM1 0%
ST FTRM2 -5.5%
LT FTRM2 0%
FUEL SYS CLSD
ST FTRM12 99.2%

also I changed one injector on cylinder 4 and clean the spark plug no carbon fouling. Let the engine warm up then took the MAF sensor off ran for another 10 mins and still had no fouling on it. Only on that cylinder.

 

-5% to +7% are normal fuel trims

I think the MAF sensor is KaPut
Hook it back up and if they jump to -20% again swap MAF out

 

ST FTRM went to -23.5
LT FTRM went to -15.5

 

MAF is reading heavier air than actual air weight so computer is calculating longer open times for injectors, and then after O2 sensor feedback its having to shorten Open time by 25%, -23.5%

So exchange the MAF sensor

Without the MAF sensor data the computer uses a table to calculate injector open time based on RPMs and throttle position, for a 3 LITER engine, which is just math
The MAF sensor weighs the incoming air by how much it "cools" the heated wire inside the MAF, heavier air cools it down more
But MAF only samples 10-15% of the air flowing passed it, so error in the computers calculatrions is TIMES 10 when MAF is off a bit

 

Swapped it out, different brand
ST FTRM -23.5%
LT FTRM -14.1%
fuel sys clsd
coolant 183%

still no fouling on cylinder 4 that has a new injector other cylinders have fouling

 

Not making much sense

Rich i.e. "-" Fuel trims come from over reporting of air weight(MAF or Air Temp sensors) or Higher than expected Fuel pressure

Could be Computer has "lost the plot" as far as calculating air/fuel mix, but no way to test for that, outside of eliminating other causes and being left with "computer error"
But my problem with that is that it did show -5% fuel trims without MAF data

 

Is it possible that when I disconnect the MAF sensor that computer cuts the injector timing down to were it sprays less fuel since it doesn’t detect air flow?

 

Yes, disconnected MAF sensor causes computer to use pre-set air/fuel mix tables, i.e. injector open times, since it doesn't have air weight data

Air "flow" is already known, a 3 LITER engine pulls in XXX volume of air at XXXX RPMs at XX throttle position, that's all just Math no unknown variables
Unknown variables are Air Weight(MAF sensor) and Air Temp(IAT sensor)

Air Weight changes alot, seal level up to 5,000ft elevation(Denver) sees a BIG change in the weight of the outside air, and the air pressure

"Hot air rises" why?, because is Lighter than cooler air, it's how a hot air balloon works
So outside air temp is also a factor, although not as big a factor as air weight from MAF because air temp tends to not vary much once its thru the air filter

All this matters because gasoline's air/fuel ratio is 14.7:1, 14.7parts air to one part gasoline, and this is a WEIGHT RATIO
14.7 pounds of air to 1 pound of gasoline
14.7 grams of air to 1 gram of gasoline

This is why Fuel injectors are rated in POUNDS of fuel flow per hour, not gallons or liters, POUNDS

So the air weight is the biggest unknown variable when calculating the air/fuel mix

 

This is the injector the previous owner installed. No

identification on them at all

 

Are all the injectors the same?

Or is that a "one off"

 

All of them are the same cheap looking blue ones like the picture. The only thing I can I think is that these cheap injectors are staying open too long or maybe they are bigger injector. They hold pressure but this would be the last thing I can think that would need to be replaced.

 

Check the 8th digit of your VIN
VIN "U" for gas only
VIN "V" for Flex Fuel

As far as I know Rangers only had the 3.0l in Flex versions from 1998 to 2003

These are the stock injectors https://www.ebay.com/itm/OEM-FUEL-IN...-/274395465515

2001-08 Ford Ranger, Mazda B3000, 3.0 V-6 (U) code gas engine.
They are rated at 13.5lb/hr, 13.5 pounds and hour, which is generally known as 14lb/hr

If someone replaced them with, say 19lb/hr, then you would get Rich codes like you have now

 

Yeah mine is “u” vin. I’m going to order those and hope that fixes the problem

 

I put the new injectors in and cleaned the other 5 spark plugs and what a big difference in idle. Got the codes p0172 and p0175 but I need to clean the o2 sensors. Which should fix it hopefully but truck is running way better
ST FTRM WAS AT -5%
LT FTRM was at -23%