I don't know what all rebuilding includes, but having a running problem with mine recently, I just bought the $12 kit ,with the filters and tip covers, and installed it myself, with a few tips from Youtube. I had one that was spraying fuel constantly, which I replaced with one from TBSCShop.com's ebay site.
On that saga, It was a real head scratcher.. I had a bad miss even after replacing my bad injector; no codes of course, so I capped of every possible vacuum port, swapped out the DIS, swapped out the MAF, front harness, coil pack (which I knew there was nothing wrong with, but I had to confirm it), new spark plugs, and each plug wire swapped out and tested.. No fix.
Finally, just to complete the check list, I swapped out the EEC.. car fired up and ran perfectly..
I've never had an EEC go bad on me.