I have 2002 f250 7.3l with 248k,and factory injectors. I just figured out that two of my injectors don't work well when cold, but once the oil heats up, they are good for the rest of the day. Cleatus helped me diagnose my issues, I ran a buzz test when cold, then when warm, and could hear the difference.
Injectors are in my future, and based on his suggestion, will probably run 160 80%.

There are no electronic tests that showed an issue, but the buzz test lists you hear the mechanical problems. He said I could aim them to buy some time, but will probably just replace them.

 

I love my 160/80 injectors. You will need a stronger transmission though, these things really wake a 7.3L up and put out a lot of torque.

 

did you ever get your transmission or shifting issues figured out?

 

Well... pretty much. I didn't really do anything different or change the tuning, I just adapted a little better to what I have. After a 2800 mile cross-country trip, you learn a lot about your "new" engine. I've noticed that the cruise control doesn't really act like it used to before the work I did. When I engage it, the speed drops a MPH or two, and that causes the CC to suddenly stomp on the throttle to get back to the target speed and that leads to the sometimes perpetual downshifting. It gets into a loop where the stomp increases the speed so much that the it backs off the throttle enough and it upshifts when the speeds levels off and then drops a little, so it applies a lot of throttle again, which causes a downshift... UGH. I had to learn how to feather the throttle down to let it land on the target speed more softly so it wouldn't get into that cycle, but that was a PITA and I had to do it again every time it shifted back into OD after a hill. I also found that it was MUCH worse when I used CC at lower speeds. If I set the cruise at 60 MPH, it was constant gear hunting. If I engaged at 66 or 67, it settled in to OD without as much babysitting. When it's empty, I notice the same behavior but since there's no load it doesn't cause a downshift. I still saw and heard the throttle changes through the turbo whine and the gauges and now that I know what to look for I see the same behavior unloaded.

To be fair, I had my truck loaded with more than it was made to handle. I had 1500 lbs loaded into it before I even hooked up the 9000 lb trailer with the 1400 lb tongue weight. I'm interested to see what it's like the next time I pull my RV without all the extra weight of moving across the country with all my tools, books, etc.

Next time I get tires, I'm either going to go back to the stock 265s or get a lift/tire/gear package and get it to where OD is usable while towing at 60 MPH. As much fun as it is, I'm just not completely comfortable with pulling around my setup going close to 70 MPH. The speeds I referred to above are speedo readings with the the 285 tires I have. 67 MPH on the speedo = 69 or 70 on the GPS. I would really like to be at about 2100 in OD at 60 MPH. I'm not much of a speed demon and with the bigger injectors it seems happier there anyway.

I've been driving it around empty and I have absolutely zero issues with it though. I also never heard back from gearhead so I'm not really impressed with their support.