What should I do for a tune up on a 1993 Sierra 1500, 5.7L TBI?

Fuel filter maybe, if you want you can spary some intake cleaner in there too

Also air filter, and you might as well check all the fluids, and grease the front end too, while you're at it.

PCV valve should also be replaced since its only $2-$4 and they aren't cleaned at every oil change interval like they are supposed to be. Also since the fuel filter was probably never replaced both of the line nuts will be rusted onto the line. If you can get one nut to break free you're in the clear. Unscrew that nut from the filter and then unscrew the filter from the other side. If not then this will not be a simple task and it will be better left to a mechanic. It will also be an expensive job at a shop because they may want to replace the whole line, so if you want to try this on your own read on.

Also make sure if you're going to replace the filter on your own you need to get line wrenches. The filter is a 20mm and the line will be a 16mm the line wrench will make contact with 5 sides of the nut any other wrench will only make contact with 2 sides of the nut and have a high possibility of crushing the nut causing it to not seal properly.

You only need to read this if you want to try to replace the filter and both nuts wont budge. Doorman makes a fuel line repair kit for this exact reason and you will probably only need one. Take a picture of the filter and lines and put it on here and I will photo shop instructions on the picture as well as explaining how to do this further in text.

Thank you, I anticipated this to be a winter/spring project as it is a seasonal work trick. I appreciate the information and will add the image when ready to begin the work.