"Under the car" covers a large area. Directly under the driver's seat you find the universal joints.
Exhaust leak? Vacuum leak?
Possibly a worn engine and/or gearbox mounting or exhaust mounting
coz ur momma is in ur bonnet!
the ball joint is going out mite wont to fix it befor it brakes it will tair alot up under neath
Also, Check for a bad motor mount The most likely cause is worn CV joints in the front two wheels. I'm assuming this is a front wheel drive model. The sound is usually most noticible when accelerating or decelerating while turning.
That'll be the carrier bearing. This happened with my Audi A6 quattro. On my model, it was more cost effective to replace the entire driveshaft than to pay for the labor to replace just the bearing.
Lifters ticking.
Under Vladimier Lenin, Russia began collectivization. This process continued, and did accelerate under Josef Stalin, who followed Lenin. But, Stalin did not cause the acceleration, the communist philosophy that Russia followed called for collectivization.
A bad transmission. The sound is from metal grinding on eachother.
Just had that problem on the rear of a Lexus ES300 and it turned out that both rear sway bar frame bushings were worn out. After replacement the car sounds quiet.
i had an 86 tc and now have an 88 tc, both hissed when in drive but goes away as i accelerate. I never found anyone who can pin point the source but I've been told its a vacuum leak. http://wiki.answers.com/Q/What_is_a_vacuum_leak
Vacuum leak in a/c door control system . Look for vacuum leak under the hood.