2007 Prius with problems and I need advise

Any warning lights/error codes?

Does the exhaust smell different?

Signs of leakage around headgasket?

At what rate is it burning oil?

Did you let oil level get really low at any point?

 

I've run into similar symptoms from a mom who let her teenage driver loose with her Prius... Was suspicious about possible aggressive driving combined with not adding oil led to these same symptoms. Evidently the lack of oil can often first show up as a misfire error code due to excessive crankshaft vibration. Once I changed the oil and the plugs it took a while for things to settle down and stop throwing misfire error codes. But car has been running without issue for more than 6 months.

So if you're interested, it might be worth buying an oil pan gasket and dropping the oil pan and seeing if you have any metal dust in it... Or just do an oil change.

 

I can't imagine how a bad bearing in a planetary gear based transmission is going to cause the engine to run rough... Make sure you measure how much oil you remove, as well as smell it. If it's a blown headgasket it could have radiator fluid in it.

And you do know that it's perfectly normal for Gen2 and Gen3 to run rough at start of cold startup right?

 

maybe a clogged intke manifold?

 

Yeah... Now that you've done the fluid changes I'd suggest you buy an intake manifold gasket and do a super thorough cleaning and inspection of intake system to see if you find anything out of the ordinary.

Most people just do a throttle body cleaning by stuff rags down the intake and using lots of carb cleaner, but a couple weeks ago a guy got on here and said he found it hardly took much additional time to remove the manifold for a more thorough cleaning.

And once all that checks out, I'd do a compression on the cylinders to make sure all those numbers check out.

And assuming you already tried, but disconnecting the 12v reboots the system and is essential to doing after tune ups and clean outs.

 

Misfires are not caused only by spark plugs....

most common.....
spark plugs
coils
fuel injectors
loss of compression
really bad air-fuel ratio/mixture
excess carbon build up

Cold Start misfires? see above plus it's sometimes caused by the MAF, among other theories. What about minor head gasket issues possibly putting a bit of fluid in that cylinder?

Google cold start misfires. It'll give you plenty of paths to travel.

 

Random misfires are indicative of possible blown bottom end of motor. Seen many of those on this site. The vibration from the knocking distorts the fg/pg pulses from the cam/crank sensors and the engine ecm see's it as multiple misfires.

Did you just buy the car?

High mileage G2's usually suffer from some level of oil loss from worn piston rings. Many people become aware of the oil loss problem when the check engine light comes on from no oil in the engine. Usually too late. A good one of those will cause bearing damage in the engine.

Top 2 reasons G2's are sold or traded in on the spot is bad hybrid battery or engine eats alot of oil or the new #3 the brake actuator has failed and dealer hits them with a $3000 bill. Traded in on the spot off it goes to auction.

No one checks there oil anymore especially on this car and especially if the oil changes are done at the dealer.