My '89 740t begins to spool fine, then still blows black smoke above 3000 RPM with loss of power.

Entire intake/intercooler system after the AMM was gone over. No leaks.

A known good AMM was swapped in. No change.

A new FPR installed . No change.

No wires, hoses, pipes loose or deteriorated.

Temp sensor is relatively new.

Garrett T3 turbo itself has a little play, but not a killer. Not blowing much oil.

I cant't figure it out, and don't want to just keep swapping in expensive parts.

Any ideas?

O2 sensor?

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'Can't understand why people abort Volvos, either' '89 740 Turbo, 122,000 miles