I bought a 2nd hand iDSI year 2003 model in 2005. For years I had the same issue with my iDSI:
1) The car vibrates at lower speed
2) The gear judder, upon acceleration. Even change the CVT fluid, after a while, it judders again.
3) Loud sound (like a metal friction) upon engaging my CVT to D and become worst when switch ON A/C
Been sending to Kosmo Kar SC in Glenmarie, they've tried to solve my CVT issue with no luck. Keep replacing the oil, have been thinking of getting a new CVT (2nd hand). Problem remained the same
Until one day, when the SC finally saw it and solve my prob.
1) Car vibrate at low speed = replace EGR valve (cost me almost 1K)
2) CVT judder = replace start-up clutch (cost me almost 5K including installation)
3) Loud sound (like a metal friction) upon engaging my CVT to D and become worst when switch ON A/C = replace flywheel due to loose spring.
Until then, my car was a good as new. Problem on the CVT and the EGR valve was confirmed, when I read upon a blog that someone had the same issue before (can't remember where I found the thread)