How to fix AFM misfire on 5.3 Chevy

In this video I will show you how to fix a misfire p0300 problem with DOD/AFM (displacement on demand), (active fuel management) system on the 2005-2010 GM 5.3 V8 engine. IF you are having a misfire on cylinders 1,7,4,or6 you may have a lifter getting stuck in the deactive cylinder position or collapsed lifter. This Hack will turn off the DOD/AFM system so that it will no longer collapse the lifters or deactivate cylinders. This hack will make your engine run in V8 mode all the time and never switch to V4 mode. (Warning: this WILL make you check engine light come on and stay on.)

[donniemathis]

This guy deserves a Nobel peace prize!

[nv]

This is good info.
AFM - will go down in history as one of the stupidest ideas that GM has come up with. Best thing I ever did was stick a range technologies AFM delete into the obd port on my 2011 5.3.

[davo]

06 Avalanche was doing this...unplugged the brake sensor and it absolutely worked....Thanks for sharing this hack!!

[markbrown]

This was soooo helpful! I was having the EXACT same problem on the EXACT same cylinder! Mine is an 07 Avalanche so the sensor location was different but it still worked! My local garage that I've trusted for years wanted $3, 000 to replace both heads and valves along with gaskets and labor. But after unplugging that sensor it ran fine and would still use the V8 and 4 cylinder modes! After a week and a half I decided to plug the sensor back in for the heck of it and it's STILL running great and getting the same mpg that I was before the problem started! Thank you sooo much again!

[buntnik]

Excellent! I too would take this option and top it off with a small piece of black tape over the check engine light…

[imnickcampos]

Another simple fix is on your gear selector, switching it to M5. It will keep you in v8 mode all of the time without much compromise, the only annoying thing about it is having to do it every time you drive the vehicle.

[dustengrier]

I'm literally about to get bundled up and go out in this snow and this 15 degree temperature to see if this fixes my issue. If i wanted a 4 cylinder i would have got one. Thanks man

[jasonwirth]

Hey man I dont ever leave comments on anything but you really helped me out. My 09 avalanche has been a beast. I thought for sure at 270k it needed a new motor when I got p0306. Watched this video and my truck is running like a champ

[donboehner]

Thanks for this. My Buddy is currently having this misfire problem. 👍

[jessiehephner]

This is a temporary fix, these engines come with a high volume oil pump to collapse the lifters and you can disable the system with a tuner as well, but eventually when the lifters permanently collapse your engine will start to bog down randomly and oil will bleed into the intake and cylinder walls, because the afm mechanical parts are still in the engine and you will get random misfires on those certain cylinders plus the camshaft will still try to activate/deactivate those cylinders because it's still physically in the engine. I took my intake off after having oil seep into 2 of those 4 cylinders and my intake had literally 2 quarts of oil in it

[jasonlewallen]

Unreal! Was gearing up ready to order lifters etc etc etc. 👍🏼

[joshleal]

Very helpful. Same problem just on cylinder 6. Thanks 👍

[cujo]

I would have thought that even though you were able to disable the AFM, that the lifter would have still been stuck. Apparently, it was able to unstuck itself after you disabled AFM. I just ordered a Range module to disable my AFM, so hopefully, I'll avoid the stuck lifter problem and not have a check engine light staring me in the face. The issue I could see with having your check engine light on after your fix, is that if something else were to go wrong with the engine you wouldn't know it, since your check engine light is already on.

[jonathanb]

Tow/Haul button will also keep it full v-8, only drawback is remote start will NOT work while the check engine light is on, not a big deal though if you don't use it much.

[THEPAGEBURNER]

Hey man I can't thank you enough I been dealing with this after replacing everything you are the man

[r.wesleydukes]

Have a 2011 5.3 Silverado. I tried an AFM DISABLER, it worked sort of for a week then back to shuddering. I'm going to try this now.

[detroitjohn]

Deleted AFM program. wire wheeled all exterior grounds. including one under dash cover. (costs nothing) started back up with 5-30 Amsoil signature /3500 max oil change. Using 5x detergent gas. Flawless performance. More pep. shifts stronger. 1.5 MPG more. But most important: no more codes on dash ! Stock except for MSD copper core plug wires. 2014 Silverado 4.3 V-6, 83K.

[alanwhite]

This works. It fixed my 2007 Silverado

[anthonyrodriguez-folz]

A Gold Nugget, Great info. Much appreciated.

[davidedgerly]

I have a question. I have a 2008 Suburban 5.3 and I want to prevent the problems that arise from the AFM & DOD. If I replace the valve cover with the new baffle and then do the tune to the ECM would that prevent the engine light from coming on? Thanks for your hard making this video...