I'm back. I took my truck into the Aamco that did the work on my transmission a year ago and they said I've got codes for the O2 sensor, multiple misfires, misfire on cylinder 5, the solenoid something-or-other in the transmission, and god knows what else. He told me I need a tune-up and a new EGR valve. I told him I already replaced the plugs, the PCV valve, the EGR valve, and that I have a K&N air filter. His exact words were "hmmmmmm?" So, I think I need to take it to an Isuzu dealership. I'm thinking that they're the only one's who might have some kind of idea what's causing all of these problems. So, I'm right back where I started.