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Juan Crespo
Juan Crespo, Tech Trainer
Category: Mitsubishi
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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1 misfire on 2007 Mitsubishi outlander. New coils and plugs

Customer Question

1 misfire on 2007 Mitsubishi outlander. New coils and plugs but extremely frustrated. Bought used and started having trouble after 1 week. Drives fine until warms up then runs extremely rough at around 2000 rpm. Please help
Submitted: 1 year ago.
Category: Mitsubishi
Expert:  Juan Crespo replied 1 year ago.

Just co confirm, are we talking about code P0301?

Customer: replied 1 year ago.
The vehicle has 170000 miles and I bought it from a car lot so know nothing about history. First code said #1 coil needed replaced (can't remember that code). Changed all coils and plugs, now says p0301
Customer: replied 1 year ago.
Let me correct that last. Changed all the plugs and the three coils behind/under the intake manifold. Since I had to pull the intake I wanted everything new before I put it back together. #1 is on the back of the engine right?
Expert:  Juan Crespo replied 1 year ago.

OK. First let me clarify that a code can only indicate that a particular circuit is out of parameter, not that a component needs to be replaced.

Bank 1 is the side of the engine closest to the bulkhead/firewall. Cylinder 1 is the one closest to the passenger fender.

P0301 basically means the onboard computer saw the crank speed slow down when it was cylinder 1's turn to push. Now this can happen due to several reasons, most common of which is a lean condition.

How is the idle with the trans in Park?

Customer: replied 1 year ago.
It seems to idle fine. I don't hear any miss. Autozone was who told me that the #1 coil was bad. No surprise they led me wrong
Customer: replied 1 year ago.
Maybe just a very slight miss now that I have it running
Expert:  Juan Crespo replied 1 year ago.

Ahh... Autozone... the place full of wannabe-mechanics whose main goal is to sell you parts - last I heard, there are some counties/states that have banned auto parts retailer such as Autozone from "diagnosing" vehicles.

Back to our issue, with the engine running at idle, spray choke cleaner on and around the EGR valve. If the engine smooths out, the EGR valve is bad and needs to be replaced. I've attached a couple of graphics showing the EGR location.

Please let me know what you find.

Customer: replied 1 year ago.
I honestly could not tell any difference in the idle. I am not even sure that it is missing at idle. It only becomes noticeable around 2000 rpm while driving
Expert:  Juan Crespo replied 1 year ago.

OK. That tells me it's probably not the EGR valve and certainly not an injector problem, which leaves us with ignition as the most probable cause. The next step would be to determine if the problem is with the primary or the secondary circuits. Since the coil was replaced with no effect, I'd say the issue lies with the primary circuit.

Taking all necessary safety precautions, have a helper run the engine at 1500 RPM power-braking it in Drive while you backprobe the #1 coil connector Black/White wire with a LED test light (DO NOT use a regular test light). If the light doesn't flash brightly and rapidly, chances are the connector or the wire to the PCM are faulty; or worse, the old bad ignition coil burned the driver in the PCM.

Can you check and let me know?

Customer: replied 1 year ago.
I am sorry but it will be tomorrow before I can run this check. I live in a small town and will have to go find an LED test light
Customer: replied 1 year ago.
I am a little concerned that I may have been spraying the cleaner in the wrong area. The picture was not very accurate to my vehicle. I sprayed in multiple locations on the rear/drivers side of the motor to no noticeable effect
Expert:  Juan Crespo replied 1 year ago.

Not a problem. You can use a good signal from another coil as reference, just don't backprobe the White/Red wire.

If the EGR was the problem, the misfire would go away when the engine got over 1500 RPM. Let's focus on the primary ignition circuit for now.

Customer: replied 1 year ago.
Can I come back to this link to post results of the back probe tomorrow and continue from there?
Expert:  Juan Crespo replied 1 year ago.

Yes, the chat will stay open. I usually login from 2-8PM ET

Customer: replied 1 year ago.
Thank you and I will reply tomorrow
Expert:  Juan Crespo replied 1 year ago.

Looking forward to hearing from you then.