I had a mystery misfire on cylinder #3 5.3l 2016 for sometime that Gm couldn’t figure out. It turned out after changing plugs and wires and swapping coils and even an injector, that it was the ignition coil connector. The wires had came lose in the plug. Bought a new connector and heat shrunk it on and it works perfect! Cost about 135$ Canadian from gm! Food for thought if anyone else is having a mystery issue.
Great way of deduction. 👍 Process of eliminating potential variables when you don't have a way of knowing what's faulty. Especially for those who don't have a scanner on hand. Reliable methods like this are invaluable.
Great video. Just ran into this problem. Solved my P0305 misfire. Thank you so much. Went ahead and also replaced the fuel injectors because of the poor idling. 2014 Silverado with 69K miles, they were total trash.
@@AnthonyJ350 yes, it’s got the GDI engine. Unfortunately the intake ports looked terrible. I couldn’t blast it with crushed walnuts like I’ve seen done so I opted for a Lucas GDI cleaner. At $20 a bottle I hope it helps. They are not building these trucks to last past 150k.
I move the coil in say misfire cylinder 5 in it say random misfires what can I be? I change the spark plug in the cable wire and the coil and still have the same problem
So my problem is I get the p0300 code and no follow up code to tell me the cylinder. You had the code and instead of replacing you moved it for the person to come back. Smh
Look into this, you might have a water leak and potentially damaged electronics if changing those parts didn't help czcams.com/video/Rjy4sqzzHgI/video.html
@davidlockwood254 Did you ever find out what the issue was? My sierra is giving me the same code. I pulled the spark plug and also had oil. Replaced them all and swapped ignition coils but still giving me p0301 misfire. I’m looking into the fuel injector now.
My truck just started misfiring in the cold, goes away when its got. My bets the intake valves caked in oil, because theres no fuel to wash the vales in direct injection engines. Huge problem in VW anyways.
I just did a cam and lifters on a 14 5.3 . It runs good now. The cylinder that was misfiring is now fine. But now i have a P0300 and a miss under load on #6. Could be coincidence and need an injector now. I have 180 psi on cyl 6. At idle i get no misfire count. But in drive power braking #6 misfire count goes up steadily. Any advice ?
@@AnthonyJ350 i had replaced only the coded coil and spark plug (misfire cylinder 8)… so my dumb ass purchased all the coils but was to lazy to change them… so decided to change them all and new spark plugs and problem went away
2015 Tahoe police package. Misfire #7 I changed #7 came back again Send it to the shop they saying we need to dig inside the engine to find out the problem.
Any chance you can share what values (misfire counts) are shown on your scan tool for all cylinders for the L83 5.3. I have some low count misfires that won’t throw a code just yet is there a normal amount of misfires for cold start and or when the engine is warm idling?
Obviously….just trying to see if you know common readings for misfire counts on these motors…like are they all supposed to read zero when warm or do they have a few on cold start…that kind of info
I’m getting p0300 and a p0420 even after changing the cats, plugs, wires, o2s and coils but when I view the freeze frame it cycles between 300 & 303 so I’m going to change out the #3 coil again and see what happens if that doesn’t help do you have any other advice?
Me and my grandfather are very confused we have p0300 cylinder 1 misfire we tried moving the coil packs and the spark plugs and wires but it still stays we also replaced the purge valve Cadillac converters pcv valve when starting the truck it pings and the motor rattles just bought the truck a month ago any information would be greatly appreciated
@@AnthonyJ350 thanks, i suspect U0401 is causing misfire i swap coil and put new plug and wire, put new ABS sensor on 4 wheels, put new o2 sensor on s1b1 and still getting misfire and U code. i will check wiring.
@@AnthonyJ350 yeah.. But you did the cyl 1 sapped to cyl 5. Maybe that means P0301 and P0305. What's your basis that the P0300 code refers to Cyl 1 or Cyl 5?
I had a mystery misfire on cylinder #3 5.3l 2016 for sometime that Gm couldn’t figure out. It turned out after changing plugs and wires and swapping coils and even an injector, that it was the ignition coil connector. The wires had came lose in the plug. Bought a new connector and heat shrunk it on and it works perfect! Cost about 135$ Canadian from gm! Food for thought if anyone else is having a mystery issue.
Thanks for sharing your experience!
Nascar race today
Was it a P0300 code? Or was it a specific cylinder code?
Great way of deduction. 👍 Process of eliminating potential variables when you don't have a way of knowing what's faulty. Especially for those who don't have a scanner on hand. Reliable methods like this are invaluable.
Thanks Thizz!
Great video. Just ran into this problem. Solved my P0305 misfire. Thank you so much. Went ahead and also replaced the fuel injectors because of the poor idling. 2014 Silverado with 69K miles, they were total trash.
Nice! Is your truck the newer one with direct injection?
@@AnthonyJ350 yes, it’s got the GDI engine. Unfortunately the intake ports looked terrible. I couldn’t blast it with crushed walnuts like I’ve seen done so I opted for a Lucas GDI cleaner. At $20 a bottle I hope it helps. They are not building these trucks to last past 150k.
Good job.! Audio, Lights, Aftermarket Equipment and now Diagnostic Troubleshooting Repairs....
You never know what we're going to work on next lol
I second that hold ratchet by the top for precision fastening
Thanks for watching!
Where can I take my car is 2018 Tahoe has rondom misfire
Broad question. What area do you live in?
I move the coil in say misfire cylinder 5 in it say random misfires what can I be? I change the spark plug in the cable wire and the coil and still have the same problem
Curious, watch this video and see if this is also your problem czcams.com/video/Rjy4sqzzHgI/video.html
So my problem is I get the p0300 code and no follow up code to tell me the cylinder. You had the code and instead of replacing you moved it for the person to come back. Smh
I did put in a new ignition coil pack, what are you talking about. We just moved it around to verify the problem....
2016 Silverado p0301 changed coil pack pulled spark plug oil on threads replaced spark plug and still same code missing when acceleration jerking flashing check engine light
Look into this, you might have a water leak and potentially damaged electronics if changing those parts didn't help czcams.com/video/Rjy4sqzzHgI/video.html
Lol they did that to eliminate the possibility of an injector ot bad lifter. Better to swap and test than throw parts at it
@davidlockwood254 Did you ever find out what the issue was? My sierra is giving me the same code. I pulled the spark plug and also had oil. Replaced them all and swapped ignition coils but still giving me p0301 misfire. I’m looking into the fuel injector now.
@@luismejia5448 mine was a valve spring and just ended up doing a dod/afm delete stage2 cam
@@AnthonyJ350 valve spring
My truck just started misfiring in the cold, goes away when its got. My bets the intake valves caked in oil, because theres no fuel to wash the vales in direct injection engines. Huge problem in VW anyways.
Definitely want an oil catch can to slow it down. Tracy Lewis Performance makes a great one for these trucks rxcatchcans.com/ols/categories/catch-cans
Have po300 and po50d on 16 silverado 5.3 do i need new fuel injectors or sparkplugs?
Not sure
I just did a cam and lifters on a 14 5.3 . It runs good now. The cylinder that was misfiring is now fine. But now i have a P0300 and a miss under load on #6. Could be coincidence and need an injector now. I have 180 psi on cyl 6. At idle i get no misfire count. But in drive power braking #6 misfire count goes up steadily. Any advice ?
Did you try moving the coil pack, just incase?
@@AnthonyJ350 Turned out to be a clogged GDI Injector
@@TheChrisgralnic Ahhh ok. Glad you figure it out!
I have a 2015 chevy tahoe, gave me a p0308 and replaced coil and sparkplug. Now i get p0300. Any ideas
You replaced all the spark plugs and how many coils?
@@AnthonyJ350 i had replaced only the coded coil and spark plug (misfire cylinder 8)… so my dumb ass purchased all the coils but was to lazy to change them… so decided to change them all and new spark plugs and problem went away
@@cmr22 Glad you figured it out
2015 Tahoe police package.
Misfire #7
I changed #7 came back again
Send it to the shop they saying we need to dig inside the engine to find out the problem.
Did you try moving it to another cylinder. It might be the wiring or pins in the connector.
What are they checking in the engine? Do they want to pull an injector out?
That’s what confusing me for a simple misfire and already cha
@@TDinosor47 I would check for a vacuum leak as well czcams.com/video/yNeWl2czii0/video.html
P0300 is random misfire though... it doesn't really help nail it down
Any chance you can share what values (misfire counts) are shown on your scan tool for all cylinders for the L83 5.3. I have some low count misfires that won’t throw a code just yet is there a normal amount of misfires for cold start and or when the engine is warm idling?
Vehicle is long gone and back in service.
Obviously….just trying to see if you know common readings for misfire counts on these motors…like are they all supposed to read zero when warm or do they have a few on cold start…that kind of info
@@trevernash1260 Sorry, I don't know that info.
I’m getting p0300 and a p0420 even after changing the cats, plugs, wires, o2s and coils but when I view the freeze frame it cycles between 300 & 303 so I’m going to change out the #3 coil again and see what happens if that doesn’t help do you have any other advice?
I would go over all the factory ground, especially the ones from motor to chassis and body.
@@AnthonyJ350 will do thanks man!
How much for repairs ?
I don't remember. I might have been 3 to 4 hours billable time due to diagnosing and testing.
Me and my grandfather are very confused we have p0300 cylinder 1 misfire we tried moving the coil packs and the spark plugs and wires but it still stays we also replaced the purge valve Cadillac converters pcv valve when starting the truck it pings and the motor rattles just bought the truck a month ago any information would be greatly appreciated
When starting the truck it also tells me to service stabilatrack abs trailer brakes we were thinking pcm
*ecm*
Look into this first. You might have a water leak in the roof czcams.com/video/Rjy4sqzzHgI/video.html
What cause aggressive and Loud downshifts in some cars?
In an automatic?
@@AnthonyJ350 yes
I wish it were this easy.
We got lucky here
@@AnthonyJ350 I had a Toyota a couple weeks ago and now a 2019 5.3, figured both would be a simple coil etc. and ended up engine damage. 😟
@@peterl2017 What was the engine damage you found?
Hey man I did the coil swap and it went from P0307 to p0300, do you think it’s the coil
Most likely if the problem moved to the position you moved the bad one
Why just swapped out coil in first place
What if it's not actually the problem?
P0300 Cylinder #1?
It's a misfire code. Need to verify which cylinder.
How did you fix U0401?
Reseal the Onstar antenna that lets water in causing issues czcams.com/video/Rjy4sqzzHgI/video.html
@@AnthonyJ350 can code U0401 cause misfire? I am having P0301 and U0401. I already sealed that antenna.
@@BALJITSINGH-ez4nk Probably can because it's a data communication error and the ignition and fuel timing is computer controlled.
@@AnthonyJ350 thanks, i suspect U0401 is causing misfire i swap coil and put new plug and wire, put new ABS sensor on 4 wheels, put new o2 sensor on s1b1 and still getting misfire and U code. i will check wiring.
@@BALJITSINGH-ez4nk I would also check for water damage
Where is the P0300?
That's the engine code
@@AnthonyJ350 yeah.. But you did the cyl 1 sapped to cyl 5.
Maybe that means P0301 and P0305.
What's your basis that the P0300 code refers to Cyl 1 or Cyl 5?
My 2017 Silverado is throwing p0300 but no specific cylinder code. I think that is what he meant.
@Vigus Finlay , P0300 means multiple misfires maybe from multiple cylinder. Could be wrong.