[jdmccright]

MMO is a little thinner than mineral oil as far as I can tell, and is supposed mix in with the gas. With all I went through to check the injectors, I'm suprised I forgot to write this in. I usually give the occasional treatment Seafoam, but heard/read good things abt MMO as a good maintenance additive. Been using it in the Envoy and ol' truck with no problems, so I figured why not?

I actually pulled all of the injectors out, rigged a 12V power supply to hold open the injector solenoid, squirted some cleaner in each, and used pressurized air (set to ~40psi, same as fuel pump pressure) to force the cleaner through the injector. Also installed new o-rings and grommets after the cleaning and reinstalled. I did not see any odd spray patterns or effects of wear.

I also forgot to note that the fuel filter had previously been changed as well, just due to age. Thanks for the response!