knocking on passenger side of engine

I have a 94 caprice with a 5.7 liter engine.Recently i have been hearing a knocking sound on the passenger side of the engine.I took off the valve covers and to check the lifters and the rockers and they seemed to be fine.But knocking still there.Cant figure out what the problem is.I was woundering if the exaughst manifold next to the engine could be causing the problem. cause after 1hr of running around the starts to not pick up speed fast enough need help. please

Specifically, is it a "tick" a "knock" a "thud" or does it have a sort of ringing to it? Odds are yes, it's probably a manifold tick, but a little more info could help to narrow it down. Does it do it more at idle or while accellerating? More in neutral or under load?

The sound is like when i push on the gas it makes the sound like a raddle and while im picking up speed foot still on the gas but as soon as i take foot of the gas the sound goes away. oh after 30 min or so the car dosent pick up speed fast enough and the inside of the car on passenger side feels hot

mine does this too although mine sounds more like a "tick" i was told its an exhaust manifold air leak or something like that. i plan on having my whole exhaust redone eventually anyway, headers and all.

Well the heat on the massenger's side could verywell mean an exhaust leak. A rattling sound could be made if the exhaust least is just severe enough but not too bad where it sounds like a loud rumble. My truck has a rotted manifold flange that finally decided to start leaking all of a sudden and it sounded like severe detonation under accelleration (sound of piston "slap" or more commonly called pinging. Some people describe it as the sound of bolts rattling in the exhaust). Scared the crap out of me at first, but a new manifold fixed that right up.

Sounds like a bad cat. The rattle sound is the broken apart catalyst inside. After warming up the car it won't really want to accelerate, plus that would be the built up heat your feeling. I've seen this many of times. To be sure, have some one lightly and carefully power brake the car and listen by the passenger side underneath to see if thats your rattle. Good luck.

Sounds like a bad cat. The rattle sound is the broken apart catalyst inside. After warming up the car it won't really want to accelerate, plus that would be the built up heat your feeling. I've seen this many of times. To be sure, have some one lightly and carefully power brake the car and listen by the passenger side underneath to see if thats your rattle. Good luck.

I agree, it could be a broken catalyst. Just don't 'powerbrake' the car too much, or transmission damage can and will occur.

Use the old garden hose trick (one end to ear, other move tilt you hear noise) or a stethoscope to isolate the source.