Replace spark plug and gaskets but now it sounds horrible and sluggish power

What is your question?

What is the possible reason for the lack of power and extreme noises and chugging like noise no as fast rpm way more than it used to need and shifting sucks

What makes this problem better or worse?

Speeding up starting and shifting

How long has your 1993 Mitsubishi 3000GT had this problem?

Weeks