Air/fuel ratio

[M151A2]

I have noticed the car slightly lurching at steady RPM.
Air/fuel ratio moving from 14 to 15. Vacuum although steady, it slightly moves during this time.
This started about the same time I installed the BMRP comp exhaust and that coincides with having a lot of rain around here.
2016 GT with Roush Phase 2 blower and Roush tune. Cover is on the filter housing.
I will have my Snapon ethos updated on Monday so that I can look at it but thought someone here might give me a heads up.
BTW pulled the MAF and it was warmer than I would have thought. Not hot, but really warm.

What say you?

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[HISSMAN]

Sounds normal to me.

 

[M151A2]

Lurching during steady rpm sure doesn't feel normal. When the A/F moves you can clearly hear it in the exhaust and feel it. It is erratic almost like a miss. No wrench, but something is not right.

 

[NoVaGT]

I have this too. Just a Bama tune, no other mods.

Between 1500RPM and 2100RPM the engine/car stutters & bucks under maintenance throttle/light throttle. I just got done data-logging the engine, and BAMA has the info. This morning I got an e-mail from them asking if I had an AM CAI, and I replied it is stock. I did notice that this bucking/stuttering started after I installed a new OEM air-filter.

There has also been CELs with misfire codes, and I've had to do the crank position re-learn 3 times in the last month or so.

The BAMA tuner guy says that there is an over-fueling issue at low RPMs.

This is very frustrating.

This morning I returned the car to the stock tune, and while the stuttering/bucking is less, it's not gone. So I'm thinking there's something else amiss.

 

[Obsol3te]

I have this too. Just a Bama tune, no other mods.

Between 1500RPM and 2100RPM the engine/car stutters & bucks under maintenance throttle/light throttle. I just got done data-logging the engine, and BAMA has the info. This morning I got an e-mail from them asking if I had an AM CAI, and I replied it is stock. I did notice that this bucking/stuttering started after I installed a new OEM air-filter.

There has also been CELs with misfire codes, and I've had to do the crank position re-learn 3 times in the last month or so.

The BAMA tuner guy says that there is an over-fueling issue at low RPMs.

This is very frustrating.

Give ole Ken Bjonnes of Palm Beach Dyno a try

 

[NoVaGT]

Give ole Ken Bjonnes of Palm Beach Dyno a try

Well, I'm thinking it's not the tune, it's something else. The car only has 8k miles on it, this is very frustrating.

Plus, ya know, I'm in Virginia.

Anyways, I've checked the lid on the air box to make sure it's tight, checked the part # on the air-filter to make sure it's the right one. Looked at the connections to the airflow sensor to make sure it's fine......

Dunno, scratching my head at this point.

 

[Obsol3te]

Well, I'm thinking it's not the tune, it's something else. The car only has 8k miles on it, this is very frustrating.

Plus, ya know, I'm in Virginia.

Anyways, I've checked the lid on the air box to make sure it's tight, checked the part # on the air-filter to make sure it's the right one. Looked at the connections to the airflow sensor to make sure it's fine......

Dunno, scratching my head at this point.

He does remote tuning as does Bama. You don't have to be in Florida to benefit. I'm in NC and have his tuning atm.

If it were something mechanical that's going wrong, you'd think it would affect your car throughout the rpm band. Bama just said theres a fueling issue down low, so... have them fix it...

 

[M151A2]

I have pretty much determined the Roush air filter is getting wet out at least very damp restricting airflow. I will plug in the scanner and look at MAF signal on sunny days and rainy days.
No rain today and it runs like a raped ape.

 

[M151A2]

Problem solved. MAF graph showed small plateaus that coincided with the small lurches.
Replaced MAF. No more " RPM hunting " after start when warm, no more lurching.
I guess getting a MAF wet due to a soaked filter does damage it.

 

[Bluemustang]

Problem solved. MAF graph showed small plateaus that coincided with the small lurches.
Replaced MAF. No more " RPM hunting " after start when warm, no more lurching.
I guess getting a MAF wet due to a soaked filter does damage it.

Do you have an oiled air filter? Maybe oil gumming up the MAF? I am interested to know what caused the MAF to go bad.

 

[M151A2]

No, a dry filter. Left the cover off the air box. Rain poured in from the hood vent and saturated the filter. Sucked water into intake and MAF.
I assume the MAF didn't like that. I leave the cover on the air box now.
Lesson for me learned.

 

[King-FlippyNips]

I've noticed mine 2015 doing this. Car is stock with no tune. It does the RPM hunt on cold crank up and every now and then it'll buck with low throttle. I still have the original air filter at 18k miles. I haven't gotten any codes though. A/F looks a little rich most of the time (usually 13.9-14.1 cruising). Wonder if I should clean the MAF....

 

[M151A2]

Might work. I think the water damaged mine. Still running strong.
The sensor isn't cheap.

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