05 GMC envoy XL 5.3 weird check engine light


	Auto Repair Home	SEARCH POSTS	WHO'S ONLINE	LOG IN

Automotive Repair

Car Troubleshooting Topics
  Car Troubleshooting
  Engine Troubleshooting
  Engine Fault Codes
  Electrical and Wiring
  Transmission Problems

Car Repair Topics
  Car Making Noises
  Car Stereo Repair
  Heating or AC Issues
  Motorcycles and ATVs
  Tricks of the Trade
  Truck Repair Advice

Site Options:
  Login
  Sign up here!

Latest Forum Post

2011 Dodge Nitro OBD scanner seems to drain battery in 10-20 minutes

When I bought this car in summer 2023, a...

Grounding Cable, 2017 Jeep Renegade Trailhawk

The Cable that connects my negative batt...

Rough Idle (Found new thing)

Hi everyone. First of all sorry for bad ...

equipment

hey yall. im a first year engineering st...

HELP

I have a 1956 1/2 ton panel truck, 69 35...

Howdy

    Just wanted to s...

ABS/Tractiob/Brake Lights on But No DTCs

Hello all, Recently while driving m...

Chevy strut replacement

I'm trying to get a sensor of some kind ...

2020 suburban new transmission and issues after install

recently had the transmission fail at 11...

Caliper piston post cleaning won't screw in

Hello, 2013 Hyundai Elantra limited (ma...

05 GMC envoy XL 5.3 weird check engine light

Sign up here!

Email This Post

Auto Repair Home>> Automotive World>> General Discussions

Dirrkdiggler420
New User

Jul 17, 2022, 6:19 AM

Post #1 of 3 (969 views)

05 GMC envoy XL 5.3 weird check engine light	Sign In

I have a 2005 GMC envoy XL V8 5.3 when I accelerate too quickly or stay about 40 mph for too long the check engine light comes on if I back off it goes off the code it throws for is for a number 4 misfire or comes back as a random misfire. No can tell me what the problem is.

Generic codes: P0300 cylinder 4 misfire
P0303 I cant remember if this one is right. This is the code for a random misfire I believe

I changed the injectors a coil pack for number four check the wiring everything looks good I can't figure this out

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jul 17, 2022, 2:27 PM

Post #2 of 3 (955 views)

Re: 05 GMC envoy XL 5.3 weird check engine light	Sign In

It's been all day with no response so I'm not sure - so you know. I'd have checked plugs or just tossed them didn't see if you touched them or not? Because of picking on one cyl. like that would see spark plug evidence vs another helps and if some miles over the 100k mark just check compression of that one for just way too low?
Oddly only knew of two (chance - alone shop thing) went forever without issue now gone.
Another here said oil getting into plug was common was news to me BTW.
Not sure if fuel pressure would or could set those codes so would check it both pressure and that it holds,

T

Double J
Veteran / Moderator
Double J profile image

Jul 17, 2022, 6:39 PM

Post #3 of 3 (944 views)

Re: 05 GMC envoy XL 5.3 weird check engine light	Sign In

P0300 is the Random Misfire code
P0304 is Cylinder #4 misfire

It sounds like you may have a sticking lifter on Cylinder 4
Common on these AFM (DoD) Engines
Active Fuel Management or Displacement on Demand
In low Engine load, The lifters on Cylinders 1,4,6,7 are collapsed, allowing it to run in 4 cylinder mode
When load is increased, the lifters return to normal .
These use special lifters on those 4 cylinders

Email This Post

Search for (options) Privacy Sitemap