In addition to the other Phil's good ideas and suggestions, especially the FPR, my first thought on reading your description was a faulty AMM. I would definitely want to swap in a known good one to see if the acceleration improves when blipping the throttle. In one of my LH 2.4 B230s I suspected the AMM was getting a bit unresponsive when pressing the gas pedal. I swapped in the one from my B230FT and the engine ran as normal. Figuring I had nothing to lose I took some supposedly decent spray AMM cleaner to it and managed to make it worse. I then decided to treat myself to a nice rebuild from Injection Labs, with the original now on the shelf as a known poor spare.

I've never heard that cleaning makes much of a difference with our hot wire AMMs. If the AMM burn off cycle starts to become less efficient then the platinum wires may start to accumulate dirt, especially during long trips. To help prevent your AMM from overheating and having a sudden failure when the air box thermostat wax piston decides to give up, the general recommendation has always been to permanently disconnect the pre-heat hose off the exhaust heat shield unless you live in an Arctic climate. You don't have to worry about BC AirCare anymore, but in the old days I used to screw the air diverter flap shut inside the air box, out of sight of the inspectors.

Unmetered air or inadequate vacuum momentarily getting in the way during acceleration could be split/loose hoses. Inspect carefully the vacuum line rubber collars on top of the throttle body for signs of splits as well as all other vacuum fittings and vacuum check valves, such as on the brake booster. Also carefully check the accordion air intake tube for splits starting in the bellows (usually out of sight underneath). Under acceleration, in addition to the vacuum changing, another thing that changes is engine torque twisting the engine on its mounts, which can momentarily open a hose split wider, especially if an engine mount has gone soft or a face of the mount has separated.

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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now