Hello 740 fans, now it is my turn to ask for help! I've got a problem that my knowledge of Volvo's does not cover. I have owned 4 Volvos but this is my first Turbo. Several weeks ago I purchased a very well maintained 92, 740 Turbo wagon with 142000 miles for my wife. Before putting it on the road I did the following:
New air filter and removed foam from air box
Checked all intake hoses, they looked good but I have ordered a new AMM to Turbo hose it is not great, but no holes.
No play in turbo
Cleaned TB
Cleaned all of the Crankcase vent system
Cleaned Injector grounds on manifold
New intake gasket
New NGK plugs, Bougicord wires and Bosch cap/rotor
New FPR, RPM Sensor and O2 sensor
New Fuel Filter, intake pump runs and main pump sounds good
Checked and replaced vac. lines
New water pump, hoses, heater valve.

Since we started driving the car it had one small moment where it would not accelerate, but about 10 seconds of that and all was fine. This was just after filling the tank with gas. Yesterday it did the same thing, but it would not run well enough to drive. For about 3/4 of a mile it had no power but would not stall. It idled fine but would not go over 10mph. My first thought was a turbo hose blew/came off, but they were good. The car sounded like it was building boost, but wouldn't accelerate. I shut the car off, it re-started but still did not want to move. Finally after limping around, it took off and ran fine. This too happened soon after filling up with gas. When we got home I checked for fault codes in the OBD and there were none and the check engine light was not on either. I checked the turbo hoses again and didn't find any issues.

Today I drove the car and it did the same thing again, but this time worse, to the point of it would not stay running. My first thought was the AMM and when unplugged, it did idle ok. I put in a good used one and it still would not run correctly. Same story of ok idle, but no power to move. I removed the test plug in the exhaust pipe and it ran a little better so I removed the Cat. Now it ran great and boy does the turbo sound good with no exhaust!. The Cat looked good, could see light through it and no loose material. I put the exhaust back together planning on cutting the muffler off working toward the assumed blockage in the exhaust. But when I started the car it ran great, so much for a problem in the exhaust. Once again, no check engine light and no codes in the OBD. I have also checked the TPS and it checks out ok, put a different, used knock sensor on, cleaned the connections on the power stage and radio supression relay. When not running correctly I have not seen smoke from the exhaust so I assume the ECT sensor is ok. Also when not running correctly, I removed each injector plug and with each one it ran a little worse so I'd assume no issues there or with the injector ballist.

So now that I've spelled out the details, please give me some tips on what to check next. I know I should pressure test the turbo hoses so I'll make the necessary parts. Odd that twice it happend after filling up with gas, but I don't see a connection. When the car runs, it runs great with plenty of power, but the intermittent issue is not good. Please shoot me some ideas and thanks for all the info I have learned here over the years.
Aaron