I have a 99 camry with a 4cyl that has a very loud rattle in the front of the engine. It has hardly enough power to pull the car anywhere. It has compression, timing is good, and all 4 cyl is firing. I pulled the top cover and all the lifters are making contact with the cam but I'm lost as to what to check next before I tear it completely down. The rattle is very loud at the exhaust manifold but sounds like its more in the block. any help would be appreciated.

 

A rattle or a knock?

Try using a section of rubber hose as a stethoscope to narrow down the area.

Any noise from under the timing cover?

The engine has a couple of balance shafts between the pan and block, these are driven by a gear on the crank. Any noise from this area?

If possible try disconnecting one plug wire at a time and determine if the noise dampens or goes away on that cylinder.

 

It sounds more like a rattle, almost like a heat sheild even though I know it isnt. Ive pulled the timing cover and everything looks good there. Its running around 10degrees before on timing and its all quiet on that side. Ive pulled each plug and the engine idled down but the rattle stayed. From what i can tell the sound seems to be on the side of the engine facing the front of the car, under the exhaust manifold. Right around the side of the block where the freeze out plugs are, maybe lower. The back side under the throttle body is quiet. Its doesnt get any louder or harder with more rpms but it is consistant with each rotation.

 

Does the engine have a emissions converter on the exhaust manifold, as in a combo exhaust manifold and emission converter. It possible the converter may broken inside the can. This would explain the rattle and if the pieces plugged up the exhaust system, the lack of power.

Check if the noise is coming from the can.

If not the problem check the exhaust system from the engine back. A damaged exhaust can make a rattle, as with the converter if the exhaust is plugged this will effect engine power.