1983 300d turbo

Gents, the car sat for a year. I couldn't even convince my family members to start her up for me. I came back to a bad situation. I replaced the battery, replaced the oil and filter, new fuel filter and pre-filter, and new air filter. Here's the problem, though:

When I start the car and let it run, sometimes it seems to start strong and stay running strong for 10 even 20 minutes. Sometimes after starting strong, it will sputter out and turn off on its own, even if I try to smooth out the engine by depressing the accelerator while in park.

After a long idle of at least 5 minutes, when I go to try to drive it, it loses power either right after a full stop and when I go to press the accelerator, or on uphills. On uphills it's usually completely gutless, but if I have momentum on the straightaway, and then use that momentum to turn onto an uphill, it seems to maintain its power.

In every case, when the turbo spools up, I get good power. But sometimes I come to a stop right after that good power, the engine sputters, and it even turns off completely. It never has a problem starting up again, but after it sputters out and I try to restart it, it restarts in sputter mode.

I thought a new fuel and pre-filter would do the trick, but it didn't. Oil pressure seems to be good according to the pressure gauge. I thought the diesel would have gone bad after a year of sitting in the tank, so I put about 5 new gallons of diesel in there to dilute what I thought was bad fuel. By the way the fuel tank has a brand new strainer on the bottom.

What to check next?

Thanks,

Sev

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