Hesitation possible flooding at highway speed
- Thread starter jmblocker
- Start date
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davidzog
TYF Newbie
- Joined
- Sep 29, 2018
- Posts
- 19
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- 4
Can I ask how long its been since new plugs and wires?? Had a similar issue....misfire was so intermittent that it did not set any code...hope that helps
Thanks for the reply, I just put new plugs and wires thinking that might be the case. But no didn't help??
are you sure it's not just the afm kicking on/off, (i.e. 4cyl mode) I tuned mine out bugs the crap out of me but some people don't really notice it much
2010 Yukon slt 5.3 6 speed auto 2wd. Just put new plugs and wires. Didn't help. Been doing it for 3 weeks.
Thanks!
Does the 2010 Yukon have that feature?
iamdub
Full Access Member
I'm with Doubie on this one. Press the DIC button (top or second one) to scroll through the displayed info until you see the "V4 Mode" or "V8 Mode" screen. While driving around those speeds where you feel the hesitation, watch and see if it coincides with it being in V4 mode.
not sure you should be able to check your dic as mentioned above
Ok, Thanks
Ok, Thanks... I'll check that out!
Yes it has the afm.Thanks for the help with that, however, it does feel like it has a slight misfire when in v4... Causing it to change from v4 to v8 and back again as though it doesn't know what to do. The feel of a misfire isn't present while in v8. Thanks again for your help.
iamdub
Full Access Member
Well, a V8 running on 4 cylinders pretty much IS a misfire, and 4 of them at that!
Sounds like normal operation. Like most others, your driving environment and style don't allow very much use of 4-cylinder mode so it won't stay engaged for very long the few times it actually does engage. Unless you often drive around 65 MPH or less on flat and straight roads with no headwinds for miles at a time, you're not really going to benefit from having AFM. Even if you did, the few bucks in gas it may save you isn't a drop compared to the expense of repairing or replacing the engine if (practically WHEN) an AFM lifter fails. I suggest you have it deleted if that's in the cards for you or at least disabled with a tune.
Thanks, this is new to me (AFM) first vehicle I've owned with this, and I think I want to do something to stop using it. Don't need the hassle or expenses that it may bring?
there are some simple options to turn it off, almost any off the shelf tuner will allow you to disable It, typically they run about $300, you can find them used and un-married on ebay for half that price, there is a another little device that plugs into the obd port and you just leave it there made by range technology but even those run a couple hundred. my opinion is to just get the little tuner as they can be found easier used for less and call it good. other options are to have it deleted but that requires at least a partial tear down of the engine and reprogramming the electronics.
Ok Thanks for the info.
iamdub
Full Access Member
To add to Doubie's reply: For $150, I had a local speed shop tune my PCM to turn off AFM, turn off the rear O2 sensors (for catless long tube headers), remove the speed limiter, reduce Torque Management and tweak the transmission shifting a little.
I recently ran across a guy ( >CLICK HERE< ) that will turn off AFM for $50. Your car will be off the road for a few days 'cuz you mail him your PCM. But, for that inconvenience and $50, you may greatly extend the life of your motor. If you later decide to delete AFM (replace the components with their non-AFM variant) to essentially bullet-proof your engine, the tuning part will already be handled.
I recently ran across a guy ( >CLICK HERE< ) that will turn off AFM for $50. Your car will be off the road for a few days 'cuz you mail him your PCM. But, for that inconvenience and $50, you may greatly extend the life of your motor. If you later decide to delete AFM (replace the components with their non-AFM variant) to essentially bullet-proof your engine, the tuning part will already be handled.
