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Random misfire. code p0300. 2006 escalade esvwith 6.0.

Customer Question
Random misfire. code p0300 ...

Random misfire. code p0300

Mechanic's Assistant: How many miles are on the car? Is it a steady misfire? Or random?

2006 escalade esvwith 6.0

Mechanic's Assistant: Are you fixing your Escalade yourself? What have you tried so far?

Random after being on hoghway highway

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

Yes fixing myself

Submitted: 11 months ago.Category: Cadillac
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Answered in 5 minutes by:
9/1/2017
Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago
rpmdiag
rpmdiag, Tech and Instructor
Category: Cadillac
Satisfied Customers: 9,114
Experience: Since 1975
Verified

Hi, I'm Ron and I will be helping you today.
Stand by for a moment while I prepare your answer.

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Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

That code is caused by a few different things. One is a bad CRANK sensor. Two is a vacuum leak, and three would be a plugged CAT converter. The tests that are involved can be done to confirm exactly what is causing it. A scan tool, vacuum gauge and lab scope will tell what it is.

Please understand that I don't know your skill level or tools
you have to assist us. Also understand that I can't see, smell,
hear, or touch the vehicle either, so your patience is
appreciated. JA is a great Q/A site, but it does not replace a
repair shop. So please don’t shoot the messenger if I have to
deliver bad news:)
If you are satisfied with my answer, I would greatly
appreciate a 5 star rating now before you leave the site and I
will still assist you after you have rated me too if another
question pops up. I don’t get credit for helping you until
you rate me

Thanks, Ron

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Customer reply replied 11 months ago
It has 251,000 but regular oil changes. plugs were put in 2 years ago without many miles on them. only comes on the highway.
Customer reply replied 11 months ago
intake does not seem to have a leak. and gas pressure is 56+
Customer reply replied 11 months ago
thinking maybe camshaft or crank sensor?
Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

Then I would eliminate a vacuum leak but still consider plugged exhaust and CRANK sensor as the faults. The testing will show. Also test the fuel pressure under a load too and for a plugged fuel filter.

It wouldn't be a bad CAM sensor.

Thanks again and please remember to rate me 5 stars now
and keep this link in case you need me again later on.
I don’t get credit for assisting you until you rate me

Ron

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Customer reply replied 11 months ago
Fuel pressure increased as it should given acceleration. I had thought of plugged exhaust but there is a leak at manifold so any pressure would escape.
Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

Yeah, if it's a HUGE leak, the size of your tail pipe. Check the CRANK sensor with a scope and let me know the results.

I’ve been in the auto repair industry since 1975 and have made many improvements over
the years pertaining to proper repairs. I also share this knowledge in the classrooms I
instruct in around the country, teaching for large companies who offer high-end training
to repair shop technicians.
It all starts with listening to the customer’s complaint, confirming it and finally doing all
the needed tests to locate the problem. All these tests require thousands of dollars worth
of specialized equipment that were designed and produced for the professional
technician. So when I recommend something for you to do, though it may seem silly to
you, please trust that I’ve “been there and done that” before. Getting a baseline is critical.
Once this is done, then I confirm what I have found wrong instead of throwing parts at it,
to be sure the problem I see is NOT camouflaged by something else.
Just like when you go to the doctor’s office for a visit, they take all your vital signs such
as; blood pressure, body temperature, weight, pulse etc.
This is my approach as well, except with the cars vital signs instead. I do everything
possible to NOT leave any stones unturned because it can cause you to misdiagnose the
problem or chase your tail.
I see so many people replace everything between the bumpers to no avail and spend
money they could have saved, if they only paid for a good diagnosis.
Sad to say, I even see people offering help to someone else by just telling them what the
parts are they should replace. Ouch!! These cars are all high tech, no room for guesswork.
When the check engine light or any lights illuminate in the instrument cluster, something
is obviously wrong, and there is not a code reader on the planet that will tell you what’s
wrong, they will only give you a code that is related to the part/circuit in question. These
parts stores check codes for free, for what reason? Hmm!

Thanks again, and please remember to rate me 5 stars for my time.

Ron

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Customer reply replied 11 months ago
Scan tool only gets the 300 code. I don't have a scope yet. but the crank sensor was one of my initial causes. So I will explore that further. My modis that is still working only does up to 2004. The other y/n buttons not working.
Customer reply replied 11 months ago
Can't I use a multi meter?
Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

Okay, let me know what you do find out. I'm here to help you.

A multi meter is of no value here, the capture rate of the senor is way too slow.

Thanks again and please remember to rate me 5 stars now
and keep this link in case you need me again later on.
I don’t get credit for assisting you until you rate me

Ron

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Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

Did you have any more questions for me at this time?

Ron

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Cadillac Mechanic: rpmdiag, Tech and Instructor replied 11 months ago

Thanks again and please remember to rate me 5 stars now
and keep this link in case you need me again later on.
I don’t get credit for assisting you until you rate me
My goal is to assist you in the repair of your vehicle by
supplying you with well educated information. I may not
always have the exact fix you wanted to hear, but my job is
to get you on the right track, which I always do. I can’t hear,
see, smell or touch your vehicle from where I’m at, so your
understanding of that is greatly appreciated. There are no
magical answers, but I do my best to guide you in the right
direction.

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