I bought a 92 LS400 with very low miles, as the original owner had died, it sat most of the time for years, and about 5 years back the wife had a new fuel pump installed, and had the gas tank cleaned and sealed etc., due to problems like described here. Since I bought it a few months ago I have done the following, and it has improved a lot, but the problem persists.

So far I have new spark plugs, new spark plug wires, 2 new distributor caps and rotors, two new coil packs, a can of techron, then sea foam, then Lucas, fuel system treatment, but it still surges and pops on acceleration, maybe a bit less when fully warmed. Next steps seem to be a new mass air flow meter, possibly change the fuel pump and fuel filters again, and maybe as a last resort ecu capacitors, but I am a bit out of my depth at that point. Any suggestions?