Now have 140k miles without any major problems. Started car recently and a engine noise started out of nowhere. Noise almost sound like Diesel engine running. No engine lights or codes showing up. A local mechanic diagnosed noise as a cracked part inside of intake manifold. Ended up taking in to Toyota dealership and they diagnosed as same. Toyota dealer ordered and installed new intake manifold and cleaned throttle body($780) but it didn't fix the problem. Here is a run down of what's going on. (1)Noise is heard in cabin of car thru firewall but not outside of car or engine compartment , (2)when sitting still and press accelerator to take off the car hesitates / shutters before taking off, (3)starting of engine is effected as well. Rough starts, usually doesn't start on first try. Toyota mechanic also ran fuel pressure test and it was within their spec but a little high on pressure. Anybody else had any of these issues.

 

Rattles on this engine are common. Some are normal such as valve train.

If noise occurred with other engine problems you noted. Might be the VVTi.

Suggest you find a section of hose to use a stethoscope and if possible attempt to narrow down the location of the noise. Areas to check are:

Passenger side of engine, upper section closest to the intake manifold for a rattle.

Passenger side of engine closest to firewall.

FYI, the intake manifold of some engines had baffle that broke loose making a noise.

 

Yes all the symptoms started at the same time. Toyota called today and they think it may have something to do with fuel damper. @$170 in parts only.

 

It is possible a defective damper can cause a knocking noise. This noise like water hammer in water plumbing of a house.

It can also cause the engine to run lean.

 

Water hammer is a good example.( I'm a plumber). The damper was a successful fix. Toyota did me good as they could. I only had to pay for the damper $187 after tax. It's been a leaning experience for all of us. The car now has gone back to normal. No excessive engine noise, no hesitation in accelerator from 0mph and no hard starts. Hoping for many more miles of good running. Thanks for your input on my troubles and hope it helps someone out there save a few $'s in repairs. Nearly $1000 I've got invested in this experience. And don't forget to keep your receipts in case there is a recall on these out of pocket repairs down the road.

 

Great job.

Thanks for posting back with the fix.