2010 Prius; Whole-vehicle shudder, P0304, seems unrelated

TLDR; Took it in for a Cyl4 Misfire & they tell me I need a transmission?

So...I bought this car back in September, and for most of that time I've had I can only describe as a "whole-vehicle shudder" that occurs very specifically at or around 1500rpm (give or take 100rpm or so), at pretty much any speed (from 15mph up to highway speed). Nobody I've talked to locally (nearest T= dealership/specialist is nearly 100miles away) has any idea.

In the last couple of weeks, I've begun throwing a P0304 intermittently about every 80-160 miles (so once every day or two, since I commute 80miles round-trip each day for work)...I clear it & watch to see how long it takes to come back. It's for THIS symptom that I actually took it in.

I use a Bluetooth dongle & TorquePro to display gauges, and that's one of the ones I watch.

I took it to a local grease-monkey repair shop (that's actually the name of their shop).

He said he swapped plug & coil to different cylinders, and the symptom does NOT follow either one, and the engine holds/passes a compression test.

Next I got a series of text messages (below) which are...confusing, to say the least, as one would seem to have nothing to do with the other if only because of the time-difference in symptoms.

A little input would be helpful.

QUOTE:
Hi Scott, I didn't want to wake you since this is your night time! Glad we spent the time to diagnose the car... you may or may not need plugs and a coil but that's not the cause of the misfire. In your hybrid, the transmission has an electric stator in it that seems to be malfunctioning and causing power surges that is impacting the electrical system. We recommend taking it to Toyota, as we're not setup for hybrid transmission work. It's most likely going to need a transmission.

 

Oh, I personally participated in a whole-circuit EGR & Intake cleaning less than 5k miles ago. At that time, the EGR cooler was COMPLETELY (100%) fouled, not a bit of anything getting through it. Took 30 minutes at the local carwash with the pressure-wand to unclog it. Did similar with the intake manifold & the EGR valve itself (as well as all associated piping).

Came home looking like "black-face" pretty much head-to-toe (from all the particulate), which wasn't pleasant.

Also, this is not the "engine shudder" or "engine shake" that many have experienced, usually at start-up (myself included, scared the crap out of me, I've got a thread about it already)...or at least it doesn't feel like it. It's a "whole vehicle" shudder that does not feel like it's coming from the engine compartment specifically, it feels pretty much exactly the same at any speed from 15(ish) to 70(ish)mph, happens as mentioned above right around 1500rpm...which just happens to be the RPMs needed to "maintain" a steady speed on level ground.

_______________________________________________________________

OK. On to further details from the tech.

Went to pick-up the car & got a chance to chat with him, he said (hope I get this right)...
One of the two stators in teh transmission is sending surges of AC current through the system that's playing hell with your electrical system.

He couldn't explain why it would specifically be targeting Cylinder4, but said "it can cause all kinds of wonky effects (his words), like taking out the radio, causing the Multi-display to fail, or even ignition-related stuff like this"

That's pretty much a direct quote. He went on to say "we try not to work on hybrids, beyond straight-engine-stuff" & suggested I find a Pri specialist...but suggested my tranny is shot.

 

140k(ish), and yeah...done a whole-circuit cleaning less than 5k miles ago.

 

Also, he confirmed that he did swap the plug & coil to other cylinder(s) to see if the symptom followed...it apparently stayed with Cyl4.

Associated questions:

1. He was using his SnapOn OBD tool to watch the misfires as we drove, and I watched 'em counting up as we drove...is there a threshold over which it "pops" the CEL? x-misfire/seconds (or revolutions, or miles, or whatever)?

2. Is there a way to monitor that from TorquePro with the little bluetooth ODB reader?

 

Dead link.

And yeah, that's not the first time I've gotten that KIND of answer (try to techno-babble your way out of it) when someone doesn't wanna work on something...and it's not always specifically limited to vehicles.

 

So after reading that, of which I understood maybe 20% if I'm lucky...how/where do I get my hands on that software and/or the connection to a laptop to use it?

 

I (participated in) cleared out the entire path from the EGR Valve all the way up through the Intake...took 'em all up to the car wash & blasted 'em clean.

If my air intake got completely clogged in less than 5000 miles, I've got bigger problems anyway.

EDIT:

At this point, I'm just spit-ballin' for ideas anyway, I have an appointment a week from Monday to have the dealership see if they can't figure out what the hell is going on.

 

Can't answer to the EGR Valve itself, that was cleaned by the mechanic.

The cooler was 100% clogged, took a half hour & about $10 worth of quarters to get it blowing freely.

And yeah, I blew all the holes, even the small (3/4" Diameter?) hole on one end where the EGR circuit goes in. Honestly, besides getting the cooler clean, that's where I got most of my black-face from. It was not pleasant!