Expert: Dr. Madhvendra T. singh - 1/18/2012

Question
Hi just a quick question I had someone change the throttle body on my BMW 1989 318i auto. since they have changed it my car has never been going into gears properly its seems to take a while to move up a gear then shuns in when it does. This seems to be eating a lot of petrol as it is over revving high before engaging into gear. I have changed the oil in gearbox as well. The cables to the throttle body seem loose on the accelerator side and tight on the gear change cable..The guy who did it is no help and says he does not know what he did with the old throttle body. Hope you can help as many people I've been too are baffled..

Answer
Hi Hari , changing the throttle body by an inexperienced person can sometimes engage the sports mode of the transmission permenently . This can cause the engine to over rev (red line) before it upshifts . A simple way of knowing exactly what has happened is to notice a change in pick up . Does your car reach 100 faster than before ? If so then my theory is correct . If not i would suggest you get your transmission box changed .