Little history - After letting my truck sit since 2014 to this spring (!!!) I had multiple misfire and related codes. Plugs/wires/rotor/cap only improved the situation but did not eliminate them. Couldn't find 2 mechanics to agree (I consulted 4) and this forum had some advice as well. Finally an old timer suggested a full tank of gas, 2 bottles of Techron and then park it for a few weeks then run it a little and park it for a few weeks etc. He swore that it would clean crud (or sediment) out of my injectors and lines. Well, I did about 4/5 cycles before I moved. I left the truck there for 3 months and picked it up a few days back. Damned if the Check Engine light is gone and she passed inspection! Of course now that we are in 100+ temps the AC is dead, dead, dead. But, I replaced the compressor,accumulator and a few other odds and ends about 5.000 miles (and 8 years) ago. I'm wondering about the cans of freon they sell at parts stores. I've always been skeptical about that route but realistically feel that with essentially almost new parts I may only be down on freon. What do ya'all think here? I remember in the past on other cars that "you need to evacuate your system" first but I really can't find people doing that online. Any advice is appreciated.