Recently my 84 300d has lost all power under 2300 rpm, it just doesn't really do anything. It wouldn't matter as I have never had too much power under that range, but now, from a dead stop and full ...diesel, it takes over 10 seconds to get up to 2300 ish but when it does I'm fine.

It started doing this about 400 miles ago. About 1800 miles ago (or a week) I re-timed the injection pump and cleared out the crap in the overboost protection valve and wow it ran amazing up until about 400 miles (yesterday). I checked the throttle linkage, and it seems to be fine, giving the ip all it can take. I did notice a slight leak at the ip around the first line due to the re-ttiming I did, but it has been like that since I re-did the timing. Any ideas? Also, it loses power very easily, as iin if I am going 60 and go up a hill pedal to the flo' it ends up at a crawl....