CUTLASS TH200 shifting issues

[WanaBa442]

Got a weird one going on, haven't been able to pin it down yet.
TH200 in the Cutlass behaving a bit weird.
Starts and goes fine, shift up 1-2-3 as it should. Come to a long hill, or if you want to pass a slow mover is when it happens.
Put your foot in it and make it downshift, so far so good. Trans makes the 3-2 shift, and with a mighty roar the 260 powers you onward.
Then, upshift 2>3 at the increased speed and RPM and the car just dies.....
Bucks, loses power, has even stalled if you keep your foot in it.
Pump the throttle (thinking it went lean, or emptied the carb bowl) no love there.
Let off, ease into the gas and you can usually keep it running.
Thought it was a carb vac leak causing the issue, but find nothing.
Reset TV cable and seems to shift a bit better than it did but still has the passing gear blues.
Carb accel pump is good, ignition seems fine, trns fluid is clean and full.
????

 

[WanaBa442]

Replayed the scenario again today.
Starts and goes fine 1-2-3 under light throttle.
Have a decent hill nearby, ran from a dead stop and held it in second gear.Goes like stink until manually shifting into 3rd.
Then drops up 1000 rmp, surges, bucks, revs up a bit, dies again.
Let off and ease back into the gas and it'll come out of it and cruise along.
Anything more than 1/2 pedal brings it on, but only in 3rd?
Convertor? Trans?
Any ideas?
Have a TH350 in the garage that needs a rebuild, it may be that time......

 

[Wageslave]

Sounds a bit like timing, but if you want to confirm it's not the transmission, unplug the 4 pin electrical connector on the side of the transmission to disable the torque converter lockup. Try to replicate the issue again and see how it acts. If it continues, it is likely an engine issue.

 

[WanaBa442]

TH200, no lockup in place.
2.5 speeds forward, 1 reverse

 

[TexasT]

Sounds like you are running out of fuel. Fuel filter new? what about the filter at the carb inlet? might need a gauge on it taped to the windshield to see if the pressure is steady as you make these attempts.