1991 Toyota Cressida Surge while driving

Engine Mechanical problem
1991 Toyota Cressida 4 cyl Two Wheel Drive 110000 miles

Good day

I got the 21y carburettor engin in my car and in your question and answers you explain one for a fual injection engin.

Are there any explanation for this engin.

Hope you can help

Thanks
Schalk van Zyl