MAF / Stalling question (HELP)

[Meat coyote racing]

Hello!

So, the question I have is can I switch out a MAF sensor on the car when the car already has a tune?

The reason I am asking this question is because when I am coming to a stop and rolling e.g. a stop light, I put the car in neutral and coast to a stop. While doing this, the RPMs drop down to about 500 RMPs then begins to act weird. What it specifically does is drop to 500 RPM, drops below 500, then SOMETIMES will go to 0 RPM and stall.

I'd say that this happens probably 2 out of 10 times. The other 8 times, it will hit 500 RPMs, drop below 500, bounce up to 800, drop back down etc. I watch the AFRs during this time and they are usually fluctuating between 13.6 and 14.8 while it's doing this.

A week ago I read it could be a dirty MAF, dirty throttle bottle or vacuum leak. When I began the witch hunt I removed the MAF, cleaned it, and then did the same with the throttle body (you could eat off the throttle body it was so clean). I put the MAF and the throttle body back on and the problem appeared to be solved.

This past week I got my car tuned at the best speed shop in the state (IMO) and told them to do a smoke test (no vacuum leak found). They tuned the car and I drove it home last night. I woke up this morning and THE CAR STALLED while coasting to a stop. Its worth mentioning that it ONLY does it when coasting, braking doesn't effect it (I did this to rule out the brake booster vacuum line). When the car is stopped and idling it does not present the symptoms I previously described, nor does it stall. I cleaned the MAF once again and its still stalling while coasting in neutral (about 20% of the time).

I still have my OEM MAF sensor from when I installed my PMAS CAI. I want to put the OEM MAF back on to see if the one I have in right now is faulty; however, the original one was not tuned with the car last week. Does anyone know if this matters? Any help is appreciated

Zack

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[Meat coyote racing]

The original maf part number is 8V2Z-12B579-A.

The MAF that is currently installed came with the "PMAS Velocity Cold Air Intake System with No Tune Required" kit that I installed. No internals added to the engine which require a different size.

Since it's a "no tune" required kit, I assumed the MAF that's currently installed was programmed by PMAS. However, since it was tuned last week with it installed, I have no idea if I can re-install the 8V2Z-12B579-A.

 

[Meat coyote racing]

Part number MT13-2

 

[Meat coyote racing]

Thanks!!!

 

[Voo Doo]

Thanks!!!

It’s called...Turbulence!! .. gear down to stop!!.. do not put it in neutral!! As soon as you do you close ... I think it’s called the throttle body??... now you have a mass of air intake that cannot go anywhere... it’s as simple as gearing Down..... not putting it in neural!! Try that!!

Am getting the Cervini Stalker hood complete with the RAM AIR kit!! Matt at Steeda explained I might have an issue with too much air...IF I PUT IT IN NEUTRAL THEN COAST TO A STOP!! I explained I never do!! He said...”then chances are you will have no issue with stumbling or stalling!! I think you are getting too much air, shutting off your intake and the air causes turbulence around your sensor!!

No harm in trying that for zero cost!! Let us know if the problem is solved!!!

 

[Meat coyote racing]

It’s called...Turbulence!! .. gear down to stop!!.. do not put it in neutral!! As soon as you do you close ... I think it’s called the throttle body??... now you have a mass of air intake that cannot go anywhere... it’s as simple as gearing Down..... not putting it in neural!! Try that!!

Am getting the Cervini Stalker hood complete with the RAM AIR kit!! Matt at Steeda explained I might have an issue with too much air...IF I PUT IT IN NEUTRAL THEN COAST TO A STOP!! I explained I never do!! He said...”then chances are you will have no issue with stumbling or stalling!! I think you are getting too much air, shutting off your intake and the air causes turbulence around your sensor!!

No harm in trying that for zero cost!! Let us know if the problem is solved!!!

Voodoo,

This is EXACTLY what it was! I have a MMD V Series upper and lower grill which allows much more air flow, and a Velossa Big mouth insert that was blowing directly on my PMAS intake.

I shortened a coupler by 1" 3/4 in. which brought the intake back and out of the direct line of the turbulent air and has solved the stalling issue. The car would only stall at speeds over 40mph, in neutral, so I'm confident turbulence was the culprit. I know just downshifting to a stop is easy; however, having the ability to put it in neutral without a stall is convenient (if needed). I've been driving it for a couple days now with no issues so it seems to be resolved. It seems your contact at Steeda and yourself, know you're stuff.

Thanks for the post!

Zack

 

[Voo Doo]

Voodoo,

This is EXACTLY what it was! I have a MMD V Series upper and lower grill which allows much more air flow, and a Velossa Big mouth insert that was blowing directly on my PMAS intake.

I shortened a coupler by 1" 3/4 in. which brought the intake back and out of the direct line of the turbulent air and has solved the stalling issue. The car would only stall at speeds over 40mph, in neutral, so I'm confident turbulence was the culprit. I know just downshifting to a stop is easy; however, having the ability to put it in neutral without a stall is convenient (if needed). I've been driving it for a couple days now with no issues so it seems to be resolved. It seems your contact at Steeda and yourself, know you're stuff.

Thanks for the post!

Zack

tj@steeda pls let Matt know he has helped the forum... once again!! Matt... appreciate all you do for us!!

 

[Voo Doo]

Voodoo,

This is EXACTLY what it was! I have a MMD V Series upper and lower grill which allows much more air flow, and a Velossa Big mouth insert that was blowing directly on my PMAS intake.

I shortened a coupler by 1" 3/4 in. which brought the intake back and out of the direct line of the turbulent air and has solved the stalling issue. The car would only stall at speeds over 40mph, in neutral, so I'm confident turbulence was the culprit. I know just downshifting to a stop is easy; however, having the ability to put it in neutral without a stall is convenient (if needed). I've been driving it for a couple days now with no issues so it seems to be resolved. It seems your contact at Steeda and yourself, know you're stuff.

Thanks for the post!

Zack

Hey Zack... waaaaay back in the day when my dad taught me how to drive I always downshifted!! Man did he give me shit!!! “It’s easier and cheaper for me to change the brakes than the bloody clutch” !! I still downshift to this very day!! Is there a reason you put I in neutral... or just a habit now?? Glad ya fixed it!!

 

[Meat coyote racing]

Thanks!

 

[Meat coyote racing]

Is there a reason you put I in neutral... or just a habit now??

I downshift and utilize engine breaking often; however, sometimes I throw it in neutral and coast a few hundred feet. No particular reason.

 

[natepcbfl]

Well this sounds like the issue I am having. IDK if turbulence is the factor though. Yes it has dies before while still coming to a stop, but I have also came to a complete stop and then for no reason it starts to stumble 10 seconds after stopping and then will at times even act like its missing a few cylinders when I go to take off. I do have a JLT 110 CIA with tune on it, however it just started doing it about 6 months ago and the tune has been on for a couple years. Thought it was bad gas so switched stations a couple time with no change. Very intermittent too, I may go days or a week and its fine then all of a sudden its acting like a turd.

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