Can't figure out the problem

spark plugs, coils?

 

did you get the original denso plugs and coils? I've read lots of the aftermarket stuff doesn't work.

You can try moving the #2 cylinder coil (seems to be good) to the other cylinders and see if changes things.

History on the car?

 

on the other hand you might want to figure out why you have 2 evap codes. makes me wonder if you're running lean...

 

P0300 I have that on my Prius. It's a brand new ride. Dealer say it was normal. Does your engine shake a lot with those misfired?

 

that's a nice print out of the codes

 

how many miles on her?

 

Bentley states, P0455 [Evaporative Emission Control System Leak Detected (gross leak)] is same as DTC P0442 (in terms of diagnosis aspects to eliminate).
P0442 - Evaporative Emission control System Leak Detected (small leak).
P0441 - Evaporative Emission Control System Incorrect Purge Flow.

Both (P0441, P0442) have the same diagnostic trouble areas to resolve:

• fuel tank cap correctly installed
• fuel tank cap is cracked or damaged
• vaccum hose cracks are blocked, damaged, or disconnected in Figure 1 of the circuit description; reference the circuit diagram for the fuel system
• open or short in vapor pressure sensor circuit
• vapor pressure sensor
• open or short in VSV circuit for EVAP
• VSV for EVAP
• open or short in VSV circuit for CCV
• VSV for CCV
• open or short in VSV circuit for pressure switching valve
• VSV for pressure switching valve
• fuel tank is cracked or damaged
• charcoal canister is cracked or damaged
• fuel tank over fill check valve is cracked or damaged
• ECM

Did you recently top off? There are quite a few valves in the fuel evap recovery; possibly one or more is stuck in wrong position. One top off is unlikely to cause this, but multiple top offs from previous owners could.

Good luck.

 

Let me get this straight. Your Prius is throwing a code, P0300, which is evidently random multiple cylinder misfires, and they are saying it's "normal"?

If your engine is misfiring and shaking a lot and throwing that code? I would venture to say that's not "normal" and investigation is warranted.

 

I have to agree with 69shovlhed ... it's a little bit unfocused to be throwing around other usual-suspect misfire causes like plugs, coils, O2 sensor, etc., all while a large evap leak is shown on the screenshot in the very first post....

-Chap

 

sounds like a trip to the dealer for expert analysis.

 

Anything, Bre'r Fox, anything, just please, never look into those evap codes.

-Chap

 

Shake meant your coil is bad. Replace 1,3, and 4 from your error code. Since you have around 80K miles. Just replace the spark plug when your doing that. Bad coil = lost of power when driving.

 

Right, that has to be it. Whatever you do, don't even think of looking for the large vacuum leak the computer is telling you about.

-Chap

 

if your engine is missing (shaking), and throwing a P0300 code, and a DEALER told you it was normal, you need to call Toyota and complain about incompetent dealer, and definitely never go there again. it is never normal for an engine to misfire. and it ain't good for the motor to misfire all the time. if it hiccupped once and set a P0300, and the dealer cleared it and it hasn't done it again, that would be one thing. but if the CEL is on, there is a problem. any competent, honest shop would try to figure it out, not lie to you.

 

not. it could be a bad coil, or bad plugs, or an injector, or a broken valve spring or ...

if it was only one cylinder I would swap the coil with another cylinder and see if the miss moves, but I doubt 3 coils gonna go bad all at once. its probably got a vacuum leak and its running lean. many times with a vac leak, you can hear it hissing while the engine idles. look for damaged or unhooked vacuum lines with a strong flash light.