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Multiple Misfire / Overheating

4K views 14 replies 3 participants last post by  Bold-Gold00 
#1 · (Edited)
[RESOLVED] Multiple Misfire / Overheating

Resolution: replace spark plugs, Overheated was a separate issue.

Okay I have had this car for about 2 weeks now, its been great, no issues at all, got the new handles in, new lights ordered, coming along nicely.
For some reason I guess I pissed her off.

I started it up to let it warm up before I drive to work, went back inside to get my coffee and lunch for work and I come to the check engine light one, wasn't running rough at all or anything I figured it would be oxygen sensor, something small. I figured since I was ahead of schedule to check the code. P0302, Cylinder #2 Misfire.
This is normal to me, I've had to change spark plugs in almost every car I've had for my family. I drove it gently to work and that's when it overheated.. got to work, let it cool (1/2 mile from overheating) Came back and tried to flash codes and it failed. Attempted to limp to autozone and change the plug. I put in an NGK Laser Platinum plug, replacing the Champion plug in the vehicle prior.

Started the car and the idle was rough for about 5 seconds before it smoothed out however during the rough idle it tripped 2 more codes,
P0300 - Random Cylinder Misfire
P0301 - Cylinder #1 Misfire
(P0302 Previously, still included)

I limped it home, once again it got hot, I'm waiting for it cool and I am going to drain the coolant and put fresh coolant in.
I need to remove the spark plug and check for oil in the combustion chamber which it most likely isn't (as pictured)

On the even number (driver side) of the engine there is oil leaking, talking with family we think it may be the valve cover gasket letting oil into threads.
Overheating caused by bad coolant.

Anyone have advice? Picture of the spark plug is contained.

2000 Dodge Intrepid with the 3.2L V6, 143,000 miles.
 

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#3 ·
Yep. As Chris says change all 6. I'd go with the original Champions if price is an issue.

What NGK did you put in? Model/Part number?
 
#5 ·
NGK were the standard plug in the 2002-2004 with the 3.5L

All others got the standard Champions RC12PEC5 for the 32/3.5L. Considering the Champions were originally in your car and you have 143k miles on it I would say they're pretty good plugs. Looking at the picture of the one plug you posted...I'd guess they've been changed at least once already.
 
#6 ·
My 2000 R/T with the 3.5L is still running fine on the original Champions at 90k miles.
 
#8 ·
I'd go with the Champions to find out if you have other problems without spending as much. You might have a coil pack issue or the spring under the coil pack.

You talk about an oil leak on the passenger side head. That's cylinders 1/3/5 on that bank. Your P0301 is a misfire in cylinder #1. Front passenger side. Which plug did you change for the P0302. That would've been the drivers front.

It's not unusual for the seals to start leaking for the spark plug tube to valve cover on older cars. That's not the valve cover gasket.

Did you take a good look down in the spark plug tube after you pulled the plug? Was there oil in there? If so then it the spark plg tube seal.

Also did you put dielectric grease on the spring under the coil pack when you replaced the spark plug? If not you should've done that.
 
#9 · (Edited)
Champions it is, I was wondering if it was a coil.

The oil is on the driver side,
On the even number (driver side) of the engine there is oil leaking
I don't recall seeing any but I will go check right now, I have a camera for my phone that will allow me to see inside the combustion chamber, so why not do that in the process.

I did not add the grease, I haven't had the COP style coils before I'm learning new things...haha I will add some right now.
 
#10 ·
I took everything out for photos and topped the coolant off, put everything back in, started smoother then last time, temp got a little above half way before it kicked the thermostat, no overheating for the 10 minute drive. I got on a little bit to receive no hesitation but the code remains, it starts with the obvious misfire ticking sound rather then just the injectors. All plugs will be replaced on Saturday morning.

However I notice a few leaks, I potentially have a coolant leak, keeping an eye on it for the next hour.
Engine oil is found in a few areas, along the valve cover and head and what appears to be an oil return line.
Inside the spark plug hole there is some debris/corrosion that I'll need to figure out how to clean without getting into the combustion chamber.

The top of the piston appeared normal, the new plug already looked burnt but the car did get hot on the way home from the auto parts store..

Reassembled and drove for 10 minutes.
 

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#12 ·
Would the misfiring cause the temp rise? It sky rockets after 10 minutes of driving, but not at idle at all.

I found the coolant leak, one of the lower hoses is leaking and the drain cock wasn't tightened all the way.

It had plenty of coolant when it overheated.
 
#13 ·
Resolved!!!

1) 3.2L's hate NGK plugs

2) 6 new Champion Double Platinum plugs made the difference, no dead coils, but they will get replaced in a month or so.

3) Overheating is found by a radiator leak I will make a new post about!!

Thank you guys for the help. I was worried I had a serious issue.
 
#14 ·
Good to hear the Misfire issue is resolved on the cheap!

Unusual that that particular type NGK caused an issue as they're factory installed in 2002-2004 3.5L engines. The 3.2L isn't much different than the 3.5L other than displacement.

I don't recall anyone talking about installing the NGKs in 1998-2001 3.2L engines though.
 
#15 ·
I like to use the higher stuff, higher heat ranges and less resistant coils, ignition stuff is fun for me.

I've never had a car picky about spark plugs. But Champions are always my next choice from NGK. I like their quality but they don't get the mileage that NGK does.

My last truck was a GMC K2500 5.7L Vortec, I experimented with E3, NGK, AC Delco Rapid Fire & Iridium and MSD. NGK got the best mileage and lasted longer.

NGK +Pro Gas + longevity + heat range capability
Champion: longevity
MSD: +pro heat range capabilty -con, longevity
E3: -con, 3 of 8 plugs broke +pro gas
AC: -con longevity, -con 1 of 16 broke

The gas mileage improvement is 1-3 MPG for the first 10,000 miles.
I made a while sheet for it and everything...haha I'm weird I know.
 
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