Toyota: 200 miles total. I usually..., toyota corolla 1999, engine internals

Question
200 miles total. I usually drive slow but now I found out engine or some check light on my right panel of dashboard. I also heard some metal piece noise on the botton of the car. When I applied the brake lightly, the car vibrated, if applied the brake in ful, no vibration.

Thanks for your expert answer.

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Followup To
Question -
I have a Toyota corolla 1999 and had an oil change in Oct 30. But I just found out last Friday that it had oil leak. The mechnical tech didn't put the cap of the engine oil tank on. The cap was missing. The oild spit out to the transmission sealant. The just did degrease but I wonder whether can cause or defect my engine.....

I don't know so much about the car. I will very appreciate it your early reply and help.

Thanks a lot!
Ginger.
Answer -
Hello!

How many miles did you drive after 30 Oct? If you hadn't loose all your oil, there will be no damage. Your car runs good even with low oil level, but you don't have to drive fast (this means higher engine stress, and in this case engine internals must be well lubrified).

Hope this helps!
Regards,
Jack

Answer
Hello!

the check light is blinking? if it does, it's a serious problem, otherwise it's an injection problem, not so bad.
Go to an official toyota dealer, they have testers to plug into your ECU, so they can read your engine error code and tell what is wrong.
About the brakes, this could be an independent problem, not engine related: your brake disks are worn out or no more straight, or maybe dirty, so when you apply a little force to your brakes you "feel" your disks vibrating. Try do some hard braking for example on a straight road, start and then break hard some times, this will clean the disks. If the vibration is still here, you must repair or change your brake disks.

Hope this helps!
Best regards,
Jack