Misfire on cylinder 1

Welcome to Prius Chat .

Some questions:

• How many miles on your Prius?
• Is the engine coolant level stable?
• Did you clean the intake manifold when the egr cooler and valve were replaced?

Good luck and keep us posted .

 

have you done a compression check?

how much oil does it burn?

 

There are many, many reason why a misfire can occur. This is especially true in your case with your car having this very high mileage on the clock. A comprehensive diagnosis is the only true way to uncover the problem. Unfortunately, there are very few shops that you can trust to do this without paying a huge chunk of money. Your problem is probably going to be finding a good honest shop. Star by looking around for a reputable repair facility that has good customer feedback.

 

I'd consider doing an engine coolant flush & replace even if the coolant is steady. Mine was steady, just a little low, so I changed it when I had similar issues to you, and like you, after having the EGR cleaned or replaced. The coolant flush completely eliminated the misfiring 100%. Its never returned since.

 

That makes zero sense. How does a coolant replacement fix a misfire?

 

old coolant = bad karma?

 

Old coolant = pH imbalance

pH imbalance = less protection

Less protection = potential problems

 

not all of them, but some number typically start burning around 100k when the egr system clogs

 

Which is first? I'd guess it's more likely that burning contributes to clogging than vice versa. Or are those independent maladies?

 

i don't think there's any consensus among the experts. your guess is as good as anyones. we'll probably know more as the 14's and 15's get up there, with the improved rings and pistons.

 

Honestly, I'm not entirely sure, but it immediately fixed the problem. Not to say correlation is causation, but all the arrows say that that's what fixed my misfiring.

 

When the coolant flush was performed, did someone add type of "cooling system conditioner" or "cooling system stop-leak" as part of the coolant flush service?

If they added an additive of that type, it would explain why your misfires stopped (assuming you had/have a leaking HG issue).

 

Nope, I flushed it myself and did nothing other than remove the old fluid and refill it with new fluid. It worked so that's all I cared about.

 

I had the same problem. But I was getting a misfire on cylinder 3. Turned out to be the inlet manifold blocked on number 3. Cleaned it out and havnet had a problem since.

Posted via the PriusChat mobile app.

 

At what miles was that work done? Maybe it's closing the barn door after the horses have already bolted: if you wait on cleaning the EGR system till the car's running rough, the engine's been running at elevated temperature for a long time: a easy-flowing EGR is instrumental in keeping combustion chamber temperatures down.

 

Hey first post!
Toyota has a service Modification for this issue.
First the wires running to the EGR need to be untapped from the main loom.
NOT THE WHOLE WAY, just where they pulled them backwards.
Then rewrap the main loom and the EGR wires separated.

Hope this helps

 

Hey RacerNate, I have a similar issue, can you send me the number of the service bulletin so that I could look it up? I took it to Toyota today but they could not figure out what's wrong (attached) mine has 127k miles.