I have a 1996 Camry 4 cyl XLE with about 65,000 miles. When started cold (first thing in the a.m.) there is a very loud rumble from under the car which sounds like a hole in the exhaust or manifold. But the exhaust system is intact according to the people who have done exhaust work on our cars for the past 15 years. When the engine is warm and I start, it is somewhat loud but almost sounds normal. When driving with a warm engine there is a noticeable noise, again as if there is a hole in the exhaust. The car vibrates when in Drive and with my foot on the brake (At a stoplight). I had the front (at the grille) and upper engine mount replaced as I was told they were broken. Vibration stopped for a day or two but has returned. In neutral there is no vibration. Reving the engine in Neutral does not produce the noise or any vibration out of the ordinary. I have had the car to my regular mechanic and another who services nothing but Toyotas. I have left the car over night and of course they don't experience the problem. Now that the temperature is getting into the low 30's at night maybe I should try again! Any help will be greatly appreciated.

 

Maybe a warped exaust manifold or a bad exhaust manifold gasket for the noise, it may get better as it warms because things expand. As far as the vibration, could bea lot of things. check the tuneup, maybe a bad injector.

 

I had a engine mount replaced twice in a month because the replacement part was defective. The noise however sounds more like an exhaust leak at the manifold asu you described.

 

I also have a 96 camry and know exactly what you're talking about. If you have that of low miles then probably you haven't replaced your timing belt. When the noise started in my car, it would do it when engine cold or in morning but would be fine rest of day as long as its been warm. It sounds like marble, bearing going bad, or something hit the timing cover.... Guess what, its the timing belt which stretches out over time and the stupid cam tensioner spring wears out also which is supposed to keep belt tension properly so that the belt is nice and snug tight. On cold startup the timing slaps against the timing belt cover and that's whats making the noise. I took mine to local shop at 90k miles because I lived with the noise which started around 50kmiles and I only took to shop because car got stranded on side of road. Found timing belt is not spinning beacause of broken tooth ribbed edges inside of belt not cataching camshaft tooth gear pulley so engine could crank.

Local shop did the timing belt routing----replace belt, water pump, crankshaft seal, camshaft seal, idler bearing at the tune of around $500(all parts were aftermarket meaning not toyota factory parts.).. and yes the noise was gone and smooth sailing until 30k miles later-----same noise came back from the same area and found out aftermaket timing belt will strecth and become loose leading to noise. So now car is not worth that much per street price,,, so I decided nothing to lose and do job right. So I search interenet and found out that you have to use toyota factory timing belt and tension spring which was update part (which put more tension then original spring)
I did the job and although it took me long time and this time I used the toyota timing belt and new toyota spring, put everything back together and everything worked great till now 30k miles and still running good and no noise.

So yes, change the timing belt but make sure use toyota factory parts... Also you don't really need to change the waterpump, seals or others---do those at around 120k miles when you do your timing belt again. Yes, repair shops and toyota dealer will tell you $200 to replace belt but recomend replace others water pump, crankshaft seal, camshaft seal, idler bearings.-----called upsell jobs for profit--, just tell them only doing timing belt, will do at next 120k miles.

Now if you are handy, just do it yourself, buy toyota timing belt around $20-30, spring $5, but you will need an impact wrench and timing gear puller which you can get at local auto parts.... But if you don't have impact wrench with compressor, then suggest let dealer or something do it,,,, but used toyota belt.

Now at 146k miles, my oil pump seal is going and needs repair, leaks like a faucet but only when car is on. when car is on, you can see oil coming from the oil pump casing housing almost behind or by crankshaft area. SHop is charging around $275 to replace oil pump seals and gasket, orings, new timing belt because old one is all oiled up and compromise and besides its cheap insurance but will be toyota factory part.