4GMs

I have owned my '03 for a few years, but admit never having to inspect the fuses until now. In the process of troubleshooting a problem I noticed several fuses simply missing. Pic offered for reference:

-No PCM 1
-No ETC/ECM


I noticed there are not even electrical stabs in the holders where these particular fuses are supposed to go. Based on a combination of past experience, the info in the Owner's Booklet and alot of recent online searches these seem like rather critical circuits for proper operation. In fact, numerous posts refer to troubles with these same fuses blowing - and I don't even have them.

What's going on? The truck operates fine. Can someone confirm that these functions are simply not applicable to diesel applications?

After I get that answered I need to tackle a persistent problem I'm having with "combination bog and refused downshift under hard acceleration" . I searched this forum and others but nothing duplicates my symptoms.

The truck:
-'03 Duramax Silverado 108k and Box Stock Condition
-Starts great. (started fine yesterday at -11F)
-Runs and GENERALLY accelerates and runs up the gears fine.
-However, if I try to hit passing gear then it just flattens out (like a rev limiter) until I back off the pedal, then everything ok again.
-Also, I noticed at about 70mph it flattens out and just won't go no faster - again like a rev or speed limiter.


I realize the default assumption might be fuel pump or at least fuel pressure regulator, but I'd like to try not throwing parts at it. I thought from symptoms and online info that it might be connected to throttle control. Or TPS or IAC if those are used on a diesel. But, the missing fuses sure has me stumped ahead of everything else..

Well, a long first post. Thanks in advance to anyone who can demystify my truck.