VAC gauge surging at low speeds

[uikube]

Afternoon everyone, i have a 2019 5.0 PP1, auto. and when i am at low speeds (less that 5mph) the VAC gauge needle with fluctuate up and down and the car will slightly surge. confirmed with tuner that its not the tune, so i figure its my throttle body or maybe a VAC leak somewhere. just looking for more input. appreciate y'all

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[WildHorse]

confirmed with tuner that its not the tune

Oh but it is the tune.

 

[loucas-2021]

if it's not the tune, could be a number of things. MAF sensor dirty or faulty, throttle position sensor, or ERG or IAC valve. hth.

 

[Pistol_91]

Oh but it is the tune.

Lies

 

[SnowFox]

Could be a VaC leak along with a few other things.

Anything to make you suspect VaC leak? Move anything around? Add anything like catch can ect?

Could be a dirty MAF sensor. Some people encounter this often some never. If you run an oil filter I think it's more prone to happen at times.

Throwing any codes? How is it after start up in park?

 

[WildHorse]

Lies

Weeeeeelllllll reload the stock tune. I'll bet my Saturday night date it'll magically disappear.

 

[uikube]

Could be a VaC leak along with a few other things.

Anything to make you suspect VaC leak? Move anything around? Add anything like catch can ect?

Could be a dirty MAF sensor. Some people encounter this often some never. If you run an oil filter I think it's more prone to happen at times.

Throwing any codes? How is it after start up in park?

Need to do a VAC leak test just in case

I did clean the MAF, maybe need a new one?

and no codes, starts just fine

 

[SnowFox]

I did clean the MAF, maybe need a new one?

I wouldn't conclude that yet. I have rarely seen that go bad. Typically I think it would trigger a code or two if it did.

Plugs all good?

 

[sk47]

Hello; Not sure if the car has one but most cars do, change the PCV valve. positive crankcase ventilation valve. These are to some degree a service item. With a 2019 probably not a bad idea anyway. These are usually not very expensive but again i have not bought one for your type car.

Replacing one can sometimes reduce oil consumption as well.

My thinking is the PCV opens and closes to allow and restrict crankcase fumes. The fumes in modern cars get sent into the intake manifold hopefully to be combusted in the engine and not released into the air. The valve is needed to prevent manifold vacuum from sucking oil.

A normally simple and not expensive chore.

Good luck

 

[bayguy]

I second the comment to reload stock tune and see if issue is there if you haven't. Seems strange to test everything else but not that and just taking the tuner's word for it.

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