Engine misfire when starting with low hybrid battery

Very vague description; more detailed info will help.

 

Did you park it with the battery low?

Usually when the battery is low, the engine has to rev up to charge it.

I wouldn’t pay it too much mind, but keep an eye on the levels just in case.

 

!! That practice is tough on the battery, and probably your mpg too. I don't see why it would cause misfiring, though.

 

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Ever checked the Exhaust Gas Recirculation system, intake manifold, looked into Oil Catch Can?

Clogging of the EGR system and intake manifold, coupled with a steady diet of oil/water/gas dreck to the intake manifold via the Positive Crankcase Ventilation system is causing a couple of common problems:

1. As the EGR system inexorably clogs the engine runs hotter.
2. The PCV system dumps sludge into the intake and likely more just flows through (as an aerosol) into the combustion chamber, carbon coating the piston rings and the EGR passages.

I would lift off the throttle body (leave coolant lines attached, no need to disconnect), clean it with carb cleaner on a cloth, check the condition of the intake manifold directly below. It's pretty much a slam dunk that it will be a swimming pool. That's the stuff an Oil Catch Can will catch.

Also, remove the EGR pipe (the connecting pipe between EGR valve and intake manifold) and check it's degree of clogging. This is just the tip-of-the-iceberg of the EGR system, but easy to get to, gives you some idea what to expect for the remainder. The EGR cooler, connecting to the exhaust, is likely to be weekest link, most clogged. There are EGR passages in the intake manifold as well, and it all clogs over time.

Some info:

Nutz About Bolts Prius Maintenance Videos | PriusChat

Good thread:

EGR & Intake Manifold Clean Results | PriusChat

Another:

Oil Catch Can, Eliminate that knock! | PriusChat

 

That's a classic symptom of PCV liquid in the intake manifold. The IM design pools the liquid at the bottom of the manifold near the throttle body and then gets sucked into the cylinders on startup. The dealer "fixes" it by replacing the IM with a newer part number which mitigates the problem but doesn't eliminate it (plus the clean new IM helps).

Until @danlatu came along we had no recourse except to avoid a quick startup/shutdown:
Oil Catch Can, Eliminate that knock! | PriusChat
(mods this thread should be stickied)

 

The coils (item 1) are $73 apiece plus shipping here:

Ignition System for 2014 Toyota Prius | McGeorge Toyota Parts

Put 4 coils in a basket and fill in your info, see what the shipping would be.

Watch @NutzAboutBolts video #13 here:

Nutz About Bolts Prius Maintenance Videos | PriusChat

It takes you step-by-step through the labourious but straight forward wrenching involved. It's not that hard, and all-in I think you could easily DIY it for around $350.

To be fair to your mechanic, maybe he's stuck with the full retail price? It's noted in the above link, $109 apiece. That would make his quote reasonable, but still: it's an easy DIY, saves $150~250.

If the plugs are going to be replaced, they require a 14 mm (or 9/16") spark plug socket, and the torque is 15 foot pounds with clean/dry threads. If you use anti-seize, I'd say use it very lightly, maybe put it on and wipe off, just leave some in the threads. And reduce torque to maybe 12 foot pounds. Use a 3/8" drive torque wrench, not 1/2", it's quite a low torque value.

 

Yeah or buy them yourself and supply to him.

 

Aftermarket coils are 229 for all 4, or 81.49 each. Since I work at a parts store, I opened a box of 4 just as a check. Three of the 4 coils in the box had a Toyota part number on them. I then opened the two single coils that my store also had in stock and found another one with a Toyota part number. That tells me the main supplier for my store chain is the same as OE. Someone will get the benefit of a 4 pack of OE coils for the price of 3 from the dealer. If you know your parts guys, they should be willing to let you do this. I make more money taking care of customers like that.

 

You can always stop by my place on your travels and we could gave this done in less than an hour.

Not a hard job at all and the windshield wiper cowling isn’t that bad of a job to remove.