Tested a 95
 

I was not impressed at all. Its not in bad shape, but, it idles very low. Owner says cause the injection pump was changes and it wont idle right.

2nd, it is very slow, I mean u floor it and it hardly moves. It goes from 1st to 2nd ok, then hangs up in 2nd, you let off the throttle then it shifts, then right away to OD and if you floor it at 35MPH it wont come out of OD.

Does this Cummins have major problems, or just lack of someone knowing what the hell they are doing.

It has 240K on it.

Yes.

That's the simple answer, to probably either question. If you're thinking of buying it and so unsure of it's condition that you need to come here to ask, then it probably ain't worth it! Unless you KNOW 100% that it's something simple you can fix or have fixed reasonably, my suggestion is walk away swiftly! I been there done that Res of comment removed

If your interested and wish to pursue it, find out if the injection pump is still under any kind of warranty by whomever rebuit it.
It could be that the pump was callibrated incorrectly.
It could just be that the idle was never set right.

As far as the shifting, this is an item that can be adjusted and again, it could just be that it was never set up right after the injection pump was put in.
Thats the "glass half full" look at it.

The tranny may have internal issues and the pump may need to be torn down again. Both can be very expensive.
Thats the "glass half empty" look at it.

As far as power, if it is stock, then yes, the earlier model years are no where near as powerfull as the later model years.

I own an almost all stock 95 (Except it has a stock 180 injection pump and a BHAF).
Even with that stock 180 injection pump, my truck can not keep up with the newer diesels.... I dont even try.
However, these Cummins diesels are fairly easy to bomb if you so wished.

Good luck on your decision.

The 95 autos are a 160hp pump, very slow stock. Also the transmissions dont last very long in any of these. Youd need to get a DTT or other quality rebuild to get much use out of it.
You can fix the stock sluggishness with a cam plate, governor spring kit and an oversized air filter.
If the truck wont idle, has it been set too low? is there a leak somewhere in the fuel delivery? Injector pumps on these dont usually die. Could be something else thats misdiagnosed.