And i think it says TVIS on the top of the inlet manifold.
copy and pasted from club4ag.com
There have been many, arguments on the issue of TVIS on early model 16 valve 4A-GE. The TVIS creates higher velocity intake charge at the engine's lower operating range by closing off one intake runner of the pair on each cylinder. Now, this is a highly effective method of making usable torque curves while retaining higher volume flow at high operating range. In most near normal applications, generally meaning light bolt-on tuning, the TVIS continues to function very well. Thus keeping it is a very good idea. However, heavier modifications including ECU, Carburetion, highly aggressive valve train/cam and internal work all present effects which create difficulty in controlling these items. For example, the triggers for the TVIS will be eliminated for carbureted applications, and it's variable induction, even if it was operational presents more complex challenge to jetting your carburetors. Heavily modified engine which greatly alters maximum rev range and shifts the power band in either direction will present similar challenges to an ECU programmer as well. In those cases it is easier to remove the TVIS and use the capabilities of the ECU tuning or carburetor jets to match your desired torque range. In short, for most basic performance upgrades, the TVIS should be kept and maintained to give nicer overall torque curve which does NOT inhibit power in any significant way.