engine stumbling/running rough while cruising

my girlfriends 2010...

about 8 months ago I did the egr clean on her 230k mile car

a month ago I was driving it through town and thought I could sense a small amount of rough/misfire type behavior from the motor.

But I rarely drive it...so dismissed it.

a week ago she is driving to see me and it starts running rough... enough for her to notice.

I decide to seafoam the car by injecting the spray directly into the intake manifold.

Car runs great for a few days then begins to stumble again. Then the yellow triangle light comes on.

She takes it to the dealer as I'm out of town and they say that the car was due for a software update and that is probably the cause of the problem and she gets out of there without spending a dime.

Next day the car is running rough again.

No idea if a code was thrown...if so it was erased at dealer.

Any ideas?

thanks

 

All good with all the levels I’ve been maintaining it for the last year change the PCV valve, etc. Cleaned the MAF about nine months ago etc. pretty sure I change the spark plugs and a few things like that about a year ago also

Thanks!

 

I'm out of town and she is on her own for now

so I could not read anything and she did not get the codes

I did clean the entire egr circuit...not just the pipe.

Pretty sure it was the first time the cooler had been cleaned...at 230k miles...and it was mostly clogged...although it was not completly


this was about a year ago.


problem cropped up in last couple of weeks

 

Yes

It was the first thing I checked before spraying in the seafoam

Immediately I suspected blown head gasket

So update: She texts to say she is put another 150 miles on the car since it ran rough after leaving the dealer and it seems to be running fine now

I will update again after a few more days as she is headed to VA (about 5 hours)

Thanks!

 

It’s possible of course...

But in all my years with all the cars I’ve owned... I’ve never had a troubleshoot that involved bad gas

Doesn’t mean it can’t happen

But the 3rd gen has so many instances of rough running ...

But hopefully you are correct and this is what caused it and it’s gone

 

Hey

no ...it was running rough and that is why she took it to the dealer

That and the yellow triangle

 

I suspected as a possibility coil on plug... but from my experience when they go they just go

and the situation does not get better

if it starts running rough again though I can check that ....actually have a spare coil on plug in my toolbox

 

I really doubt that... it was at least nine or 10 months ago

Plus to be honest if there was any residual garbage in the cooler I’m pretty sure it would just blow right out the motor and not cause the engine to stumble for a day or two

 

Thanks

I will definitely keep an eye on the oil so far it has looked fine

I’ve considered doing a compression check