So first, I never said that good information was free. An analyzer has software specific to your vehicle, is able to pull up the PI series of codes that a scanner can't even see....and much, much more. A scanner only can see the PO codes, such as you got from the A's. And as I said previously, they only point to sensor fails that report to emissions tests....which is what your $90 quote is apparently also doing based on the explanation you gave....reading the PO codes that point to sensors..not an engine performance analysis....a crap shoot.
An analyzer from Snap On or Mac is a $6000.00 tool that reads the ECU during operation and is able to see how all parts are interacting for efficiency and predictive analysis. A good, well trained tech, will plug in and put quite a few miles on driving your truck so the analyzer can log during driving loads .... not sitting in the shop on a lift. Depending on mf'er ECU design, even trans, SRS, and anti-skid codes and operations can be analyzed...and for your money you get a printed report. A code reading scanner can provide an inexpensive means of reading and clearing codes, and maybe even checking the status of the OBD II monitors (different from sensors), but that’s all. To read sensor data, history codes, pending codes, monitors etc., you need a “real” scanning tool, an analyzer, with manufacturer specific software that fully interacts with all the ECU functions during and after running all while reporting system performance all the way down to AFR and what's impacting any systems not at spec...... and the price jumps accordingly. Most scan tools do not have bidirectional communications capability. This is done for liability reasons. Most late-model vehicles have quite a few built-in self-checks that can be performed with a dealer or professional level scan tool, but running these tests requires some know-how, experience and caution. An important point to remember is that a code by itself is not a diagnosis. It is a starting point for further testing and diagnosis. The code may tell you the nature of the problem or the circuit that is acting up, but it doesn’t tell you what’s causing it.
A perfect example is your PO430 code....in my experience, it could be that one cat is shot or something else entirely, .... your miles, plus not knowing how many times your O2 sensors have been replaced, ... with an analyzer I can specifically spot a failing O2 behind the cat, which will also throw your exact code. It may not be your cat....but without the ability, which an analyzer gives, to read the voltages and their sweep speed....it's a guess that can cost you a ton of $$ if the guess is off and you replace a cat and it doesn't fix the code.
Or, consider the following causes list of PO430:
Faulty catalytic converter.
Engine misfire.
Fuel injector leaking.
Engine mechanical damage (broken ring, burned valve, etc.).
Oxygen sensor that has improper readings.
Exhaust leak.
Engine misfire may or may not throw another code in tandem depending on the source. Injector issues, broken rings, exhaust leak etc. do not throw codes specific to them. An analyzer......well, you get the point.
The 448 code, is an evap issue that, again based on your miles can be two or three different items. There are tests for each item that will isolate the actual part to replace so you can remove the code. If you do your tests and they show it's the evap solenoid and the parts vendor won't take it back if it's not the fix, you need a different supplier.
Adding injector cleaner into a near empty tank is dangerous.....and wouldn't have any effect whatsoever on the codes you put in your post. That concentration of cleaner can damage parts from injector pintle seals to the cat itself. I can't begin to guess why you put injector cleaner into your tank based on your original post or codes in your second.....just guessing, but did you walk through Autozone and you saw something that caught your eye? That's a crap shoot. That's asking for advice from people who know that you need to make a left turn at the next traffic light to get where you want to go..... and you go right.
So, you want a crap shoot.....make decisions without real information...buy cheap parts because they are cheap and throw them at the problem until something sticks. Best case...that works out to a coin toss and sometimes you get lucky. Worst case you could create new, more expensive problems while spending money on things that don't work. Some problems with these trucks are shadetree mechanic capable, and some aren't. That's when a good tech with the right tools is a handy person to know.