Hello, what could be the cause when I start the engine and press on the throttle hard it withdraws or loses power and sometimes turns off. It only works when I press on the throttle very gently until it revs fully. It also withdraws when I engage the gear and start driving. I cant press on the throttle with force. My car has a manual transmission.
Lack of fuel would be my first thought. If the check engine light is on, extracting the diagnostic trouble codes would be the best first approach to this issue.
There may be a failing sensor or a vacuum leak involved and getting the codes would assist in pointing in the right direction. Just about any local auto parts store will pull the codes for free. Once you have the codes, post them below in the comments.