1. Check engine lights always on 2. Rpms flucuate while driving and more

What is your question?

1. Light came on when i firat got it. Took it in theybreaet it said it was fine didnt know why it came on. Came on again, took positive off and back on, went off. But wont go off now 2. When put car in drive from park, rpms go up then i have to wait for them to go down before ggoing or it jolts. Same when go from drive to reverse, vice versa 3. Car whistles when accelerates 4. First time it happened. Never seen gas light before, even when it was almost empty. But filled with gas drove around, maybe 50km and gas gage went down and light came on, two or three times within 50km