When i step on the gas the bmw shakes at arround 3k RPM's, its like when i hit the gas half way the car looses power, its like i have let the gas peddal go, but i havent, what could be the problem? Its a 89 525i 5spd M20, Its just at 1,2,3,4 gear when i hit the gas halfway it starts to shake, like it looses power and then i release the gas and press it gently then works ok. So what could be the problem, please help?