^I missed his sig earlier.
Since it's "barely running", just get a copy of the FSM and start with plugs and wires. Fuel filter and fluid changes. Depending on how things improve, maybe some serious fuel system cleaner or pull the injectors and have them cleaned. Don't need a 'Tuner' for those things. I guess any trusted shop (which for me isn't a dealership) could do it if the OP isn't able or willing. And from the transmission back it's just like any other car.