PO300 after changing plugs

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

boomer632

Senior Member
Joined
Jan 31, 2017
Posts
153
Reaction score
45
Ram Year
2013
Engine
5.7
2013 5.7 with 76K. I bought the truck with 74000 on it and could find no record of it's plugs ever being changed so I decided to do it myself. Got the Mopar standard plugs and gapped the to 043. Hardest part was getting those dam plugs off of the coil packs. Drivers side was a pain. Passenger side took less than an hour. Anyways.. while the TB was exposed I cleaned the bore and butterfly best I could with TB cleaner. Put it all back together and tried to start it. Took longer to fire than usual. I think that's because of the TB cleaner that my have accumulated in the intake during TB cleaning. Once it fired, it threw a PO300 code about 10 seconds later. I shut it down then restarted it again. Fired up normally this time. Code came back after about 10 seconds. I cleared the code then took a 20 mile city driving trip. Code never came back and none are pending. Truck runs smooth and better than before. Just trying to figure out why it threw a misfire code. Any suggestions? FWIW.. the old plugs weren't as bad as I thought they would be.
 

muzz3256

Junior Member
Joined
Apr 4, 2011
Posts
4
Reaction score
3
Location
Virginia
Ram Year
2010
Engine
5.7L HEMI
If I remember right, there is a TSB about not using throttle body cleaner to clean the throttle body, but rather to use brake cleaner, so maybe that was the cause of the problem. I've always completely removed my TB to clean on my other vehicles, but haven't done it yet to the Ram, but it's next on my list.
 

Burla

Senior Member
Military
Joined
Apr 28, 2012
Posts
23,231
Reaction score
44,841
Ram Year
2010 Hemi Reg Cab 4x4
Engine
Hemi
Did you unhook the battery before changing? Anyhow, I wouldn't worry if it's gone.
 
OP
OP
boomer632

boomer632

Senior Member
Joined
Jan 31, 2017
Posts
153
Reaction score
45
Ram Year
2013
Engine
5.7
I didn't unhook battery. I'm thinking it may have hiccupped when the TB cleaner went through combustion chamber. Sonfsr so good though. On a side note.. one of the red retainer clips that locks the connector on the coil broke. Is there a way or place to get a replacement retainer clip or is a new connector needed. It stays on there pretty snug without the clip tho. That missing clip was not the reason for the misfire.. checked that first.
 

Hemi395

Senior Member
Joined
Mar 18, 2013
Posts
8,977
Reaction score
15,634
Location
Cape Cod MA
Ram Year
2013
Engine
5.7 Hemi
The red part of the connector is second stage of the 2 stage lock so it should be fine without it.

I'm about to do this very soon on my truck so if I get anything similar I'll post here.
 

BigSloth

Senior Member
Joined
Jun 27, 2013
Posts
721
Reaction score
189
Location
Mobile, AL
Ram Year
2014 1500 CCSB Black Express
Engine
5.7 Hemi
Caused by cleaning the throttle body. TB/brake cleaner is flammable, and acts as a fuel, throwing off the desired air/fuel ratio, and causes random misfires. This throws a code, and will continue to until the remaining cleaner and any dislodged carbon sludge has been burned off.
 
OP
OP
boomer632

boomer632

Senior Member
Joined
Jan 31, 2017
Posts
153
Reaction score
45
Ram Year
2013
Engine
5.7
That's good to know. So the only casualty of the job is a broken clip.
 

BigSloth

Senior Member
Joined
Jun 27, 2013
Posts
721
Reaction score
189
Location
Mobile, AL
Ram Year
2014 1500 CCSB Black Express
Engine
5.7 Hemi
Correct.

And the red clips are just a second layer of protection, I've broken like 4 of mine and they still stay on just fine
 

Staff online

Forum statistics

Threads
195,469
Posts
2,870,599
Members
156,178
Latest member
mmcquinn
Top