hello group,
i own a 1999 Infiniti I-30 car, and lately its been acting weird.
whenever the speed is above 35mph, and ESPECIALLY when i take my foot
off the gas pedal - i hear this knocking sound from the engine
compartment. the sound disappears if i apply the brake and if apply the
gas pedal. and the amplitude and frequency of the knocking sound
increases when i increase the speed. it scares me a lot when i drive
this car on the highway. also when i rev up the engine when parked, i
dont hear anything. the strange thing is the sound comes only when i
leave the gas pedal. is this something concerned with the engine???

i did not want to get ripped off by the dealers/mechanics and wanted to
get some of the group's opinion on this problem. having some knowledge
before going to the mechanic will help me atleast know whether the
mechanic is ripping me off or not. any help here is highly appreciated.

thanks,
ganesh