Help Engine shaking and abnormal noise are not EGR problems

In order to logically answer all your questions, I will ask one - have you carried out any diagnostics of your problems using equipment, scanners or Techstream?

 

Too bad you have to find out like this . But at 10 plus years in ..

 

How many miles on the car?

 

What’s the miles on it?

Possible scenario: seller noticed engine shakes, tried belated EGR cleaning, which didn’t help, figured out head gasket was failing, dumped in stop-leak and put car up for sale.

I’d inspect coolant condition, and borescope inspect the combustion chambers, preferably in the morning after driving previous day. If you can manage to pressurize cooling system during inspection it’ll accelerate coolant leakage. You’re looking for exceptionally clean cylinder top (typically coolant commences leaking in cylinder one), and coolant tears commencing from head gasket seam.

the shake/rattle is typically due to coolant in combustion chamber. The EGR system clogging causes engine to run hot, which causes head gasket to let go, start leaking coolant, which results in pistons and crankshaft struggling to get over Top Dead Centre and so on.

 

Welcome to gen3 head gasket fails. Odds are good you were scammed as Mendel outlined and a replacement rebuilt engine is the only guaranteed fix since the engine is also known for bad piston rings. Carefully watch the passenger side coolant reservoir.

Car Care Nut HG Borescope at 660s

 

Inspect the piston cylinder with a borescope. If it has a gray metallic color, unlike other soot-covered cylinders, this indicates a coolant leak into the cylinder and steam cleaning of the piston.

 

The conventional old school head gasket tests often provide false negatives including checking for combustion gas in the coolant (bubbles or using a combustion gas test kit). Compression or leakdown tests also provide false negatives on the engines. An early stage gen3 Prius hg fail leaks a few drops of coolant into the cylinder causing a temporary misfire.

Typical misfire sources like plugs, coils and injectors don't just go away. Many hundreds of diy'ers and mechanics waste money chasing those solutions. Sometimes they add problems using cheap aftermarket parts.

However replacing or swapping plug 1 might be relatively low cost even though you have to remove the entire wiper assembly and support sheet metal to access the plugs and coils. If you are going that far you could just swap number 1 and 4 plugs and coils and see if the code moves to cylinder 4.

While you have access, get a borescope test done.

Eventually with an early gen3 hg leak, the coolant will disappear faster and it will be obvious, usually when it overheats for the first time weeks or months later. By then the aluminum engine parts are warped, mandating a replacement engine.

Sometimes the simpliest methods are the costliest in the end.

 

Misfires on cylinders one and two, the usual with head gasket failure.

 

The pics add nothing to the situation. Borescope.

 

Any drop in the engine coolant reservoir level?