Mine does the same thing when I run my a/c, it mega boggs down at times, All possible tune ups have already been done, I figured its because like someone else said its only a 2.2. But havent done a compression test, I also figured its got low compression for how old it is, I can hear the timing chain at times when going slow. Could be a worn timing chain? Seems like the older and more miles mine gets it gets a little rougher running and im thinking its because the timing chain is continously wearing.
Definitely change your fuel filter. Coil packs also. Run a onboard monitor system too like Torque pro its a basic cheap system blue toothed to your phone.
Clean your throttle body, CRC intake valve and turbo cleaner is good intake valve cleaner i've used too, you spray it into your resonator while its on then let it sit. IAC & TPS should be checked too and of course the ever so neglected basic air filter, doubt that though.
Spark plug wires, some taylors from summit.