2000 civic Si loss of power
 

I recently change my spark plugs and since then I feel like my car isn't pulling as strong as it used to. I feels like sometimes it hits vtec and other times it doesn't. The told me the gap of the spark plug is suppose to be 0.52 but my old spark plugs were at around 0.38

Re: 2000 civic Si loss of power
 

That older gap doesn't seem right. I gapped mine to .050" compared to my old ones and there's a noticeable difference because I made the noob mistake of not gapping them. I'm. Sadly I don't know the exact specs, but I went to Alldata and they had .050" as the gap, so I set them to that. Is the oil at a good level? Are you waiting to the car is at operating temp? There are a few factors that play into VTEC operation.