2008 Prius Engine Running Rough - Tried common solutions

When you say the oil was a "little low". How low was it? And how many times do you let it get low? Burning a lot of oil can be a sign the engine will soon need to be replaced.

Oil is the blood of the engine, without the proper oil levels (and clean oil), the engine would slowly die.

 

Does the car run good and give good gas mileage? It just sounds rough to you?

The sound in the engine might be coming from the water pump and pulley

 

I did listen and watch the video. The water pump is attached to the belt on the passenger side of the engine. You can try and see if the noise is louder on that side of the engine vs the driver's side. If they are pretty much the same on both sides, then the noise might be from the engine.

35-40mpg is pretty low for this car. So the performance might be suffering from a worn engine. But luck would have it, these engines are cheap so if everything else is in good shape, then you can replace the engine when it fails

 

How much oil does it generally consume over what oil change interval, and do you use synthetic?

You mentioned replacing the plugs with new NGKs, which part # and where did you source them from?

Do you generally use quality "top tier gas" that contains additional detergents?

Have you tried using PEA additives in the gas tank? (Tecron, BG products, Regain, Redline, etc)

Do you possess an OBD2 code reader, or a Mini-VCI cable and techstream installed on a windows device?

 

Try replacing the NGK's with Denso 3324 (SK16R11) . The 1.5 can be finicky sometimes. Try not to buy counterfeits........

Swap the catalytic converter out. Buy an inexpensive front half assembly that includes both cats. Cut your old exhaust a couple inches in front of the resonator and install the replacement. Sell the OEM cat to recoup your money plus some. (actually a lot of 'some')

An engine has to breathe, get fuel and fire (with correct timing of those events) to run correctly.

If you're confident of the breathing and the fire, it only leaves fuel and timing..

 

Your engine is eating oil cat probably damaged.

Engine sounds bad though. Try the old long screwdriver to the ear listen trick and localize where all that noise is coming from if not the water pump.
Sounds like under the valve cover chain noise. Motor sounds whooped.

at that mileage if I was in replacing the plugs I would have pulled the valve cover off too and look in there check the chain. It’s very easy to pull the valve cover off.

listen to the valve cover and then listen to the oil pan.

what kind of oil do you use?

 

No, no, no. Your catalytic converter is probably fine as a clogged converter causing a problem at idle won't let you get up to speed on the highway.

My 2005 Prius came with NGK plugs from the factory, and it's not the only one. I'd imagine your CEL would be on if you has a spark plug problem.

Maybe take the belt off and run the engine for only a minute and see if the noise goes away?

Posted via the PriusChat mobile app.

 

The NGK plug is IFR5A11. Toyota recommends either the Denso or NGK.