2004 Tahoe: Won’t move. Code P0172 and P0175. Help!

My friend’s son was driving his 2004 Tahoe on the highway and said that the engine started revving and his speed dropped to 20 mpg. He immediately pulled over and turned it off. When my friend got there. He said that it would no longer move. He suspected low fluid, but said the dipstick read high. Not sure he checked that correctly. He also noted a new CEL and a code scan came up with P0172 and P0175   

These codes appear to be fuel related and not directly related to the transmission, but I suspect that there is an indirect electronic component that is preventing it from moving.

It’s a 2004 Tahoe with the 5.3 V8 and I suspect it has a 4L60-E. 125,000 miles, second owner for two years. The vehicle is not here and I have not seen it since this happened.

Any suggestions?

172 and 175, by my recollection, are bank 1 and bank 2 rich.  Basically the computer has run out of fuel trim to pull fuel away.  Kind of a rare problem.  Any time I see it, it is related either to a massive fuel leak into the intake manifold (stuck-open purge solenoid counts, but they are usually good at identifying this via unexpected fuel tank pressure readings) or a plugged exhaust/cam timing issue, but only on non-MAF cars.

This should be unrelated to "can't move" and "engine free-revving".

If the trans fluid is overfull and the vehicle won't move, this is kind of a clue that the pump is no longer pumping fluid and the torque converter has emptied itself into the rest of the transmission.  Usually means the filter is plugged, and if you are putting enough friction material into the fluid that you have plugged the filter, then it's going to be transmission time.

When no move happened to my avalanche, the pump impeller exploded.  The test was pop off a cooler line and start truck to see if any fluid shot out.  That’s where I would start, it’s just a little e clip at the radiator.  

That happens?  i thought it was just me...

One other weird thing that I have seen happen was on a Chrysler.  They paint their trans pans inside and out.  (They rust out anyway)  On this one weird-o vehicle, the paint de-adhered from the inside of the pan and got sucked up into the filter inlet, asphyxiating it.  Replaced the trans pan, and the filter because we were in there anyway, and it was right as rain.

I assume they checked to make sure the driveshaft was still doing it's thing?

In reply to Tyler H :

Assume nothing. 

Woody said:

In reply to Tyler H :

Assume nothing. 

A broken driveshaft will definitely cause free-revving and loss of....drive, lol.

In reply to Tyler H :

It usually also results in a very loud noise when it exits, usually accompanied by some serious other noises afterwards.

I always figured that this was why the fuel tanks are on the left side.  I have seen driveshafts not only beat the exhaust apart, but also chew through the floor.  If the tank were on the right side, the driveshaft would beat through it instead.

Oh yeah.  A 172/175 can be also caused by debris covering the MAF screen so that a disproportionate amount of airflow has to go through the sampling tube.

Again, unrelated to shoeleather mode, but something to look into.