I'd start with the basics such as getting a free scan for codes performed on that vehicle by a parts store or shop. Also try checking the belts and cleaning , re-gapping or replacing the spark-plugs, plus clean the spark-plug wire connectors on the ignition coil with a small wire brush , fine sandpaper etc.Change the fuel filter, check the vac system for cracks or loose connections, pressure test the gas system.Check or replace the air filter and PCV valve.
I'd run some gas treatment through it especially if you've not run any through it in awhile or have run on a low tank.Take a good look at the charging system's connections and wires on the battery , alternator , starter , engine block ground posts and all grounds under the hood for rust or corrosion and clean them with a small wire brush or sandpaper or a file etc.
Hope that helps and best of luck.By the way keep in mind that if that vehicle has been subjected to extreme weather and temperatures it's quite possible that a bad connection exists or moister or dirt is in the gas system.
