I've been selling auto parts online successfully since 2009 on eBay and Amazon. I started a Shopify store several years ago and results have been dismal, basically flushing $500 a year down the toilet. In my mind, there is no doubt what is needed is the ability to search for parts by vehicle (make, model, year, engine, notes) as well as show all vehicles this part fits on individual product pages. I have fitment data on most of my parts and have included a basic HTML table of that information in the product page for products created since I started this website, but that really doesn't help buyers get to the page in the first place and is not usefully for Google searching.
I'm looking for advice on how best to implement this. I don't mind spending a little money but, I can’t just throw more money down a bottomless pit without results. I have over 2,000 active SKUs, so doing a lot of work item-by-item isn't practical, however, I‘m familiar with using Excel and uploading CSV files (that's how I create pages now) which seems like a better approach. I have some coding experience and understand basic programming concepts.
Any advice/guidance will be appreciated.