Gents:

I have a 7.3 idi (non turbo) thats got 270k on it, im pretty sure the previous owners gave her a run for her money. (Note: I have already replaced the return lines a while back, so they wouldn't be the culprit here) I have a few quick questions:

I replaced the fuel filter when I got the truck, and a few days ago I noticed that the fuel filter light was winking in time with the exhaust note upon startup and then went out. Seemed that was indicative of vacuum in the filter, and I decided to change the lift pump. While I was doing the lift pump, I did the CDV and the tube behind the intake (it leaks oil down the back of the motor slowly, and I wanted it to stop leaving little spots in my driveway.)

Well, the truck seems happier, and i could swear the throttle response was better (as in, you don't need as much pedal to hit the same speed). However, this morning I went to start it at the convenience store, and instead of the usual 3 cranks it just kept cranking and cranking, and when i finally mashed the throttle it did start, but it was vibrating and running a little rough/at a higher RPM that I would expect. Not 750, but like 1000 and stumbling a bit. I immediately switched to the other tank, and after running down the road it seemed fine again. Then I switched back to the rear tank to see what it was doing, no problems. Get it home, shut it off, fire it up, no problems.

WTF? So, basically:

1) is there any chance that because of the CDV that I replaced, I am burning motor oil or something resulting in odd running behavior?

2) as to installing the lift pump properly: I bumped the cam to the low part and am 99% sure I installed it right, but I have heard the gloom and doom of what happens if you put it on top of the cam. Its the straight style, not the very bent lever. Is it even possible for the lift pump to work if its installed improperly? Or would it not have started and driven for the past 100 miles?

3) Sometimes I swear the truck wants more throttle to go the same speed. That's sorta been a thing since I got it. Also, yes shes a stock non-turbo, but there isn't a whole lotta black smoke when I hit the gas hard in 4th. Is that normal? How much ought these engines vibrate when you really wind em out (3000+ RPM)? I *think* she shakes an acceptable amount...

4) as to the weird start condition, is there anything y'all can think of thats not expensive (no IP or injectors) that I can do before I take her on an 8 hour trip in a month? I was going to replace the fuel filter again (its 2+ years old now), and run some diesel kleen in the next two tanks. Do these engines just act nutty sometimes? Like, sometimes she idles at 750, sometimes 900, rarely 1000, and there doesn't seem to be a whole lotta rhyme or reason to it.

Sorry for all the questions, this is my first diesel so I'm sorta learning as I go.

 

You are getting air intrusion to your fuel, the symptoms you describe correspond with it almost perfectly, some return kits are junk, make sure there not leaking, next check the rubber line that goes from the hard line to the fuel pump, I hope you changed that line. If not ask for the multipurpose fuel line, it's thick, rated for just about any psi or fluid. It's around 5$ a foot but well worth it.

Also be sure you have a good half a tank of fuel, the tank pickups aka showerheads all eventually fall off.

Be sure to check the factory fuel line from the selector valve to the hard metal line on the k member under the motor. Previous owners are bad about splicing in electric pumps and such

 

Honestly, just find a weekend and yank the bed.
With the bed yanked, you can:
1. replace both "showerheads"
2. Inspect the tank insides, look for lots of crud that might need to be cleaned out.
3. replace the seal on the tank sending unit/
4. If you are having trouble with the fuel gauge, replace the sender.
5. replace the seals which connect the plastic lines to the fuel tank(these are O-rings basically).

It's not that bad a task; the only issue is the stock bolts.
I took an angle grinder and cut flats on both sides of each bolt for a cresent wrench, then yanked the nut off.
I used new grade 2 hex-head bolts to replace the old special ones, none of this specialty crap.