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Discussion Starter #1
2010 Challenger SRT8 6.1 Hemi, 70,000 miles. We have had the car home with us for 3 months now in Colorado. Ever since we got home, we have had a 6 cylinder misfire consistently, we've had the occasional multiple misfire and the occasional post Catalyst running lean as well.

We did the obvious things like changing out all the spark plugs, the old ones looked like they had normal wear. When we got the next Cylinder 6 misfire code we changed the ignition coil on 6 and again we were getting few days later Cylinder 6 misfire codes again. Also cleaned the air filter because it was quite dirty. I ran a cleaner through the system about 2 months ago and right now there is 44k in the gas tank. We don't know how long the car had sat before it had a good run so we figured there might have been some build up in the engine and plus we don't know how old the tank of gas was that was in the engine when we went and got it.

I have noticed when she started after sitting all night the exhaust is very strong kind of like an old truck would smell like . At one point we thought she was acting up because we couldn't afford to drive her home from Washington State to Colorado on premium gas so she ran lean for 2 and 1/2 tanks and 1900 miles. But once we got her home we made immediately filled her up with 91 octane and a bottle of octane boost. Our next step which we will take next week will be to change out the downstream O2 sensors hoping that the combination of the cylinder 6 misfire and the post catalyst lean has something to do with one of the two sensors. If that doesn't work I will be stumped and I guess we will be taking her to the dealership to have them run her on the computer.

I have asked several different automotive people that I know, and I'm getting several different answers which makes it even more puzzling . One person told us that the gas mixtures in Washington are richer than here in Colorado and that she requires a higher ethanol rate than Colorado offers, but there are many Challengers around here that are using the same gas as everyone else without any issues, so I can't see it being that . Of course we have the altitude difference but being here for 3 months the computer should have reset itself for the altitude difference around here.

Has anyone else had this issue or maybe has an idea of what it may be? Or can you verify that I am going in the right direction with what we have done so far and plan on doing in the future to try and remedy this issue?

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Sorry to hear about that. Was there a misfire code? That may be helpful for us to try to pinpoint it.



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P0306 consistently , P0300 occasionally, P2096 two or three times

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P0306 consistently , P0300 occasionally, P2096 two or three times

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Thank you for putting up codes.

P2096

Possible causes
- Faulty Heated Oxygen Sensor
- Heated Oxygen Sensor harness is open or shorted
- Heated Oxygen Sensor circuit poor electrical connection
- Exhaust leaks
- Contaminated Heated Oxygen Sensor

Tech notes
Before replacing the Heated Oxygen Sensor, inspect the sensor connector for signs of damage, water ingress, or corrosion

P0300

https://www.engine-light-help.com/P0300-check-engine-light.html

P0306

http://www.challengertalk.com/forums/f171/please-help-check-engine-light-p0306-95995/

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Thanks i will check them out. I think I might have found the problem. While at the auto parts store earlier I made the discovery that the pcv valve may be faulty. There is a lot of oil residue around the valve and in the hose. So it's possible it's failing and since the intake is right over the 6th cylinder it may be causing the issue. So for a $10 part I will find out tomorrow if that's what's been causing the problems, once the new ones installed. I will post an update tomorrow evening.

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Thanks i will check them out. I think I might have found the problem. While at the auto parts store earlier I made the discovery that the pcv valve may be faulty. There is a lot of oil residue around the valve and in the hose. So it's possible it's failing and since the intake is right over the 6th cylinder it may be causing the issue. So for a $10 part I will find out tomorrow if that's what's been causing the problems, once the new ones installed. I will post an update tomorrow evening.

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That definitely makes sense! Hopefully, it gets fixed.
 

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Why do you say it ran lean when you couldn't afford 91 octane? I would have checked compression before changing a single part, is the cam wiped out?

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We ran her from Wa to CO on the cheapest gas we could afford. We did see lean codes until we got home and filled her with good stuff and then have only seen a post cat lean code since. I hope it's not the cam. It runs perfectly besides the minor misfire between 30 and 45 mph.

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Sounds like a vacuum leak, I think the PCV is off the #6 cyl runner, or damn close to it, so you might be right on the money. Intake O-ring is a possibility as well. As far as the rich,lean, O2 sensor failure...... Remember an O2 sensor samples air, not fuel.... If the car has a vacuum leak, the car thinks it's lean, and dumps more fuel. Same goes for bad plugs or coils, if the cylinder fails to fire, you just pushed all that raw oxygen into the exhaust, O2 sees this, and signals the motor is lean and needs more fuel. You're comment about it smelling fat is a clue. It could be a valve spring, as someone mentioned earlier, but you would definitely hear some big time valve train noise. Another guess, but rare, cam lobe might be smoked. I just overhauled a 2010 ram with a wiped out cam, the thing barely ticked, but if you saw the cam you would be in shock. Could be on the injector side of thing too....
 

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Got the new pcv valve put in. Boy was the old one bad! Completely clogged and lots of oil present. It runs a lot smoother and quieter but I'm still getting the hesitation on acceleration. So I guess the next thing is to look at the spring and check the intake o ring. I'm really really hoping it's not the cam. Keep your fingers crossed! And thanks for all the advice!

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Got the new pcv valve put in. Boy was the old one bad! Completely clogged and lots of oil present. It runs a lot smoother and quieter but I'm still getting the hesitation on acceleration. So I guess the next thing is to look at the spring and check the intake o ring. I'm really really hoping it's not the cam. Keep your fingers crossed! And thanks for all the advice!

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Glad to hear you are getting somewhere on this one! Keep us posted. I always like to learn something new from every one of us and try to remember it if I have to face that certain issue.
 

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Discussion Starter #15 (Edited)
Ok so I went to Dodge yesterday with the intention of them putting her on the computer with the hopes they could pin point what the issue is. Well an 1hr later they said they wanted to tear the engine apart cause they believe it's the cam but didn't charge me for what I thought was a through diagnostic. They wanted me to make an appt for the tear down. Yeah well all they did in the hour they had her was to do a 27 point inspection!! The same inspection you get when you take a vehicle in for an oil change. What the freak is that supposed to tell them about an engine misfire?
They expected me to be this stupid girl and say yeah let's tear the engine apart and charge me an unknown amount of money. Yeah not taking her back there, ever!
I may be female but I'm neither dence nor stupid.

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Got the new pcv valve put in. Boy was the old one bad! Completely clogged and lots of oil present. It runs a lot smoother and quieter but I'm still getting the hesitation on acceleration. So I guess the next thing is to look at the spring and check the intake o ring. I'm really really hoping it's not the cam. Keep your fingers crossed! And thanks for all the advice!

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Hey Guys: I have this same Problem with my 2012 Challenger SXT..Cylinder 6 Misfire. ONLY at idle..No power loss during normal operation...Tranny switches well...I changed the plugs...Coils...I fresh out of ideas..any ideas will be helpful...Going nuts!
 

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Ok update, got it figured out. While pulling the plugs to do a compression test, all the brand new plugs are reddish orange!! The damn thing is leaking coolant!!!!! Compression test was basically 180 psi all around which is perfect for our altitude 5000 feet above sea level. The coolant leak answers every question as to why she only threw the misfire codes. The oil isn’t milky thank goodness so I believe we have caught it in time, but still looking at $2000+ to fix. Sure wish I was capable enough to do the repairs but sadly I’m not so off to the shop she goes as soon as we have the funds to fix her. The plus side is if my husband wants to switch out the cam or do any other mods ( money permitting ) this is the time to do it AND the shop in Colorado Springs recommended to me does dynos so we can kill two birds with one stone.


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The reddish plugs are probably from all the fuel treatments, not coolant.

If the coolant isnt going down in the resevoir it isnt leaking. Also, even 180psi compression does not point to a head gasket leak.

I wouldtt dive into a $2000 repair just yet. Pull the valve cover over #6 first.

Also check the fuel injector o-rings. I had a similar problem at about 100k on a 4.7 engine when the injector o-rings hardened and started to leak air around them causing a random vacuum leak.
 

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The reddish plugs are probably from all the fuel treatments, not coolant.

If the coolant isnt going down in the resevoir it isnt leaking. Also, even 180psi compression does not point to a head gasket leak.

I wouldtt dive into a $2000 repair just yet. Pull the valve cover over #6 first.

Also check the fuel injector o-rings. I had a similar problem at about 100k on a 4.7 engine when the injector o-rings hardened and started to leak air around them causing a random vacuum leak.


The coolant level is going down and we did the compression test to help rule out a bad cam. Valve covers were pulled and all look fine.
I had planned on checking the injectors next week when I can afford to buy new o rings.
I’m wondering if we have a bad temp sensor. Today while driving, I had gone 2-3 miles and had hot air coming out of the vents before the car even registered heat. Outside temp was about 45 and I can’t see an engine that big having hot (like running temp hot) air coming out of the vents after 3 miles. As for additives, the only thing I’ve done after we replaced the plugs is run a can of 44k through her. The dodge mechanic that’s been helping me via phone from the dealership the car was bought from was the one that said the plugs say coolant leak after I told him the compression test results.
Believe me I’d love it to end up being a simple couple hundred dollar fix, and I will double check to make sure. Thanks for the advice.


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