i posted this on another section, but with no luck. ok the car is an 83 firebird, 305, 700r4 all stock. so i bought it a few weeks ago and have been driving it as a work car to and from work is all.. but i took it on a longer cruise to the next town.. 30 miles round trip..lol, while driving back i noticed a small knock noise, like an exhaust leak. so then about 2 weeks later, it got louder each day, it started to affect the driving. it only does it when i push the gas in to speed up (normal acceleration) didnt do it in nuetral. ok that was then.. and now while pushing the gas it knocks real loud and jerks the car and doesnt rev freely at all. sound can be heard very slightly in neutral. while hard acceleration- engine wont rev up but sputters and knocks loudly, barley making it to the rpms to shift gears... but cant hear anything while cruising at 60mph, unless pushing gas pedal.. checked oil, very very low.. pretty sure its probably a spun bearing, but any other ideas will help. thanks alot -<Matt>-

 

sounds like a bearing... Especially if it was run very low on oil for a while.


Other than that i would suspect detonation, either from too much spark advance or a crap tank of gas.