Crazy sound upon ICE startup

Well, just happened again today on a lunch run. Didn't stop when I reached my destination (though it was less than a mile away). Booking a service appointment...

 

Crazy!
My 2010 did this; it was very repeatable. My 2012 Plug-in has never done this.

It has to be software related. I bet there's an ECU update the dealer can apply which will solve this problem. I did note on my service records that my dealer did apply a "Special Service Campaign," but never told me what it is.

 

I had same problem and really cold days on start up. It also occurred when the engine was warmed up. Mine was a failing intake timing gear. Replaced and it is quiet again. No more rattling sound coming from engine.

 

Intake camshaft timing gear?

 

Could a failing intake camshaft timing gear produce a p0304 code?

 

I was responding to previous post, didn’t understand that terminology. I’d suspect something was lost in translation, talking with service writers, but not clear on it myself.

Can you add more background regarding P0304 code; what’s the car doing? What’s the miles on it?

 

224000 miles on it. 2010. recently cleaned the egr tube and intake manifold in response to a p0401 code which cleared that code. I thought this would address the rough start up, but it did not. I did not clean the ERG valve and am considering cleaning that and am currently trying to figure out how to get the obd reader to move the valve to ensure it is not stuck open and it functioning properly.

After this, the car threw the p0304 code. I have switched the 3rd and 4th ignition coil and cleared the code. P0304 popped up again. I put a screw driver to the fuel injector and it seems like they all function, but the 4th one does seem to be struggling.I think I am going to switch 3rd and 4th injector today to see how they look and if that moves the code. I had the spark plugs changed 6 months ago, but havent been able to get the spark plugs out yet this time myself.

All symptoms include:
-Whining from the radio which is decreased by turning the radio off
-rough start up especially if cold started, 'knocking'
-high vibrations in center counsel and passenger seat, particularly in the 2nd notch of the hybrid indicator system on the dash
-occasional hard acceleration in that same 2nd notch (putting the car to the red spot -so full gas- stops the hard acceleration)
-the first acceleration of the car seems to be sluggish
-currently getting slightly decreased gas mileage

I also am aware of a small valve cover leak per the mechanic who changed my spark plugs 6months ago. I did not change the intake manifolds gasket either as I did not initially plan to take it off, but maybe that's leaking enough to cause a misfire code?

Car also threw a B1443 code which I have not looked into yet, but have just not been using the AC/heater.

(sorry, I didn't realize at first that I had hopped to a Gen 1 room)

 

224k is late in the day for EGR cleaning. With everything you’ve described, very likely head gasket is failing.

 

Gen 1 plug in, so it’s the same engine

 

I got the prius at 210,000 and mostly trying to keep it for another year or two until I can hopefuy get a newer model.

I got the spark plug out, and it looked fine. Haven't touched the Injector yet because I realized I needed the oring.

I was thinking head gasket potentially, but there's has been no coolant loss, no white smoke, no milky oil. Would this potentially be catching the gasket early enough that I could have the gasket replaced or is it more like by time you have the problem the connecting rod is likely already bent?

 

I'm not a fan of ICE turning on in the middle of EV at high-speeds. If I know I'm gonna use ICE, I just start the car in non-EV mode to give the ICE a proper warm-up.