A tuner could fix it correctly the first try, probably. But if you intend to keep it, it will act up and the datalogger is a real neat troubleshooting aid. If you let someone use your car you will know how hard they pushed the pedal, how fast they went and when it happened. I got my son good one day. even for intermittent problems they're hard to beat. They show every sensor, what it told your ECM and when it told it. You'll know what gear you were in and if the transmission was slow to shift, you'll know why. They're just a really neat tool.
The cable can be purchased at "AKM Cables" for one. They're top notch and it'll be a OBD1 to USB cable. E-mail him and he'll tell you what you need. The datalogging program I like is TTS Datamaster. It's free for 20 logs. Each log lasts a long time. There are other free logging programs out there also. I don't know what tuners charge but I've got one I'll recommend. I've been tuned by most all of them and this guy's really thorough. I'll PM you his name because I don't know about forums, sponsors and such so a PM will be easier.