Hello,folks! Driving a 2006 F150 Lariat 4X4 SCREW with.......wait for it........wait...........here it comes..........463K !!! That's right, 463K miles! I'm a contract pipeline inspector,so, lots of highway miles and no problems to speak of. I did just recently put a rebuilt transmission in because I lost 3rd & overdrive. Anyway, over the last couple of months, when the truck gets up to temp or hot(idling on job in Austin,TX), it's started giving me some sputtering and shuddering on acceleration. When I start it in the morning or when it's cooled down, it will take off great,no matter how hard I get on it. Once it gets hot, I may even have to baby it leaving from a stop. The hotter it gets sitting in this God awful Austin traffic, the worse it gets and I have to really be gentle to keep it from missing or sputtering. Tends to be that once I'm going and try to accelerate or pass, more issues.. It's shuddering when I accelerate ,but, if I'll back off the gas and immediately get back on,it will go ahead and grab ahold and accelerate smoothly. Almost feels like the rear end,but, signs point to something electronic,the way it smooths right out if I give it a quick pedal. Other symptoms are having to baby it leaving a stop light or from a stop. If I give it too much,it will start missing and kinda shudder in the rear like I described. I've only done regular maintenance(plugs and coils,fluids) on this because I haven't had a lick of trouble. Yes, I've added the stabilizer in the rear end. Haven't even changed a headlight or brake light,yet. I'm going to go ahead and drop the $$ to give it a full complete tuneup,throttle body assembly and all. My main question is what everyone thinks should be included in the tune up and what your thoughts are as to what may be going on? It sure seems like it's all gonna be tied to something electronic and I AM NOT up to date on working on all this new stuff. I haven't ever had to do a complete tune up on these newer vehicles with all the electronics,so, I'd like to hear everyone's thoughts on what all to change. Plugs,coils,sensors, ignition parts,etc.....Thanks in advance. BTW.....my uncle was a Ford mechanic in a dealership for 45 years and told me in the early 80s, some great advice. "Check the date the vehicle was built before you buy it. Never buy one built on Mon or Fri." This truck was built on a Wednesday. Just sayin'.....