Http request taking too much time even after using PoolHttpClientConnectionManager

Question

I have a API hosted on Kubernetes and created using spring boot,in which we send request to another API. I want to reduce time for Http calls as it is taking almost 2-3 sec for calls. We introduced PoolHttpClientConnectionManager with MaxConnTotal and MaxConnPerRoute as 100. After introducing we saw that calls are showing random behaviour like sometimes it takes 600ms and sometimes it is taking 2-3 sec and sometimes more than that. We are having hard time in going forward with that randomness. We need to reduce down to best possible values as we are catering to another application which is realtime process.