Engine Misfire

[JD Olivares]

Hope someone can give me some ideas. 

I have a '14 Sierra (5.3L,2WD) with 151K miles. About 30K miles ago I changed the plugs and wires and about 5k miles ago I had a coil go out on me, but I only replaced 1 coil.

 

I currently have a slight misfire. It runs fine at idle and at WOT throttle. But when I'm at part throttle, I will feel a slight miss that gives me a light buck. It is not severe enough to throw a code, and I have not noticed a significant drop in gas mileage. 

 

Should I start by replacing all the coils? I know once 1 goes, the rest are soon to follow. Or could this be a sensor or something else?

 

Any help or insight would be great.

 

Thanks in Advance!

Edited April 12, 2023 by JD Olivares

[Snowcamo]

A scanner of sorts will tell you what cylinder is miss firing while it is.

 

Also you can just sand the plug connections of the coils and apply dielectric grease. Make sure you twist (left to right) the connectors back on to remove the trapped air so they do not push back off the connectors.

[MikeBMW]

I have a friend with a 2014 5.3 - replaced his coils twice over 200K miles.
He's not a savvy guy for automotive stuff so just does what the techs tell him needs to be done.
Once he was told to replace all blend doors on the AC vent system for $1000. I scanned it, relearned it and no problems since.
I wasn't available to scan his coils but I'm sure he was taken advantage of on the replacement of them all.
A really good scan tool can be well worth the cost once the warranty is over.
 

[asilverblazer]

On 4/12/2023 at 11:16 AM, JD Olivares said:

It runs fine at idle and at WOT throttle. But when I'm at part throttle, I will feel a slight miss that gives me a light buck. It is not severe enough to throw a code

Slight buck... not at idle... not at WOT... no misfire code... when torque converter is trying to lock... 

 

 

...may not be a miss at all.

[wesmania]

I was getting misfire on my 2017 silverado 6.2 and turned out to be a bent push rod. But I could hear the engine running rough and was getting misfire on cylinder 4 code 

[jagabom (Esquire)]

My buddy had issues with non GM wires.  Finally replaced them with GM wires and all was well.  Pricey though. 

This was 15 years ago.

Jim

CYWG.