I have received an email from a journal in the field of engineering saying that they found an article of mine and want to feature it in their own publications for a fee. I cannot tell if this is something legit or something they send to everyone they can find. I have Googled, but there is not much information on them. How can I tell?
While open-source journals can charge authors to help recoup the publishing costs in the absence of paid subscriptions, it is completely dishonest for a journal to "republish" a work that has already appeared in print. It is even more dishonest for them to charge you to do it. At best this is just an advertising service; at worst it's a scam.
I wouldn't even dignify the email with a response. Send that email into your junk folder.
aeismail's answer is 100% correct in general.
However, the place that emailed you isn't a journal, and doesn't claim to be (at least, not on their website). It's a website that prints the citation and abstract of articles published in other journals, with a link to the original article on the original publisher's website. Presumably (based on your experience), they allow people to pay to have their abstract "featured" on the website.
This is not necessarily dishonest on their part - they may be permitted to reproduce the meta-information of a published article, which is what they are putting on the website.
However, it will be of zero benefit to you to pay to have your article "featured" in this way.