Some keys are not working: 7ujm

I am having an issue with my laptop keyboard, it takes 3 seconds(sometimes longer or less) for my 7ujm keys to work on my MacBook Pro (Retina, 15-inch, Early 2013). I have cleaned the keyboard ribbon and it is not that. I have checked mouse keys, PRAM reset, NVRAM reset, clean installed Sierra and anything else I could find online about this issue. I have replaced the battery recently and this began shortly after, There was spillage in the laptop when I got it, but this has not effected the laptop before and like I said the keys work intermittently. I am assuming it is not corrosion and is a software issue as the keys often work best when the laptop has been off for a while and it is first turned on. If I plug in an external keyboard, the external keyboard works fine, but the keys on the keyboard in the laptop stay intermittent. Any help would be greatly appreciated. Thanks.