davester

and it's spam now.

That is GM's recommendation for flashing any of the computers in your vehicle, at least via their SPS programming service (vs OTA updates), that you should only flash an update if the update fixes a problem you are actually having or is safety-recall related.

they look to have significantly different tubes, so crawling under the truck and looking should tell you which you need.

If you can, you might try checking the fuel pressure going into the FPR w the key on, it should be over the listed pressure range. You might also check on charm.li (website) for the fuel pressure, it may be slightly different for the setup you have (with the FPR on the fuel rail). I think I read somewhere that it can be different from the later systems, like in my '04, where the FPR is part of the fuel pump itself.

you need to be a vendor before you post links to your business like in your sig.

If your truck has a vacuum line, that means it has the fuel pressure regulator on the fuel rail. This also means there's a inline fuel filter along the inside of the frame rail, below the driver's seat. Maybe replace that and check FP again/.

First you have to figure out how you want it to work, either automatically in conjunctionn with something else, or just manually with a switch or what.

charm.li (website) has GM's diagnostic procedures for each of those codes. GM recommends working them one at a time, lowest number up.

maybe when the trip is over, check all the other joints in the front end, like all the ball joints, tie rods, pitman & idler arms, etc...

what are the tow mirrors off?

Well, I would suggest phoning up Rough Country and making sure it's right for your truck. Or at least going through their website to check it's compatibility.

Yes, GM's recommendation is to not flash updates for anything, unless the vehicle has a problem that the update is listed as fixing (this is for any module, not just the infotainment system).

I'm sure if you went to a junkyard where you go in and pull the part off the truck yourself, not a used part place where they do it for you, you can get that part on it's own. Depending on if and what else you would be buying, and time of day, they might even just skip over adding it as a item to the bill.

No, we trade them like pokeman cards.

It would be sold as a "kit", lights + auth/programming code. You can resell the code to someone else, if they just buy the lights, either new or used, and they can then use the code to get them to work on their truck.