New help with my Bullitt

[Leigh_bullitt]

Hi Everyone
I have a 2020 mustang Bullitt and love it but I seem to have some mysterious intermittent problem with it.

when it’s running well it will pull hard sound deep and have plenty of torque.
however I could literally switch off the key and start it again and it will run ( I wouldn’t say bad but a lot less than otherwise ).

it will be jerky and sluggish in low rpm traffic it will rock during deceleration foot of gas in any gear. And the exhaust will sound different almost like it’s struggling slightly.

it is tuned but I’ve sent datalogs and they can see anything wrong with it but the difference is like night and day.
I’ve cleaned the Maf. Calibrated the throttle, the car has 24000miles.

is their anything that can change intermittently during drive cycles?.

what about the spark plugs. Could they be working ok and then not so good?.

really need your help cause it’s driving me nuts.

thanks for you help all

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[cerbomark]

Do you have an easy way to temporarily put the stock tune back in? I d see if it does It then and that could narrow down the issue if it s only on the tune map.
Doubt it is the plugs in your situation .

 

[cerbomark]

Have the plug ever been messed with? with 24000 I d say they should never have been out. Now if they ve been in and out I m not sure a cracked one(plug) will be intermittent problem?

 

[Leigh_bullitt]

Not since I have owned the vehicle from new.
it doesn’t look like the coil packs have been touched at the dealer either when it has a service.
It’s so strange. It doesn’t feel terrible but just today it was running lovely and the wheels were spinning in second.
When it’s bad it will feel like it’s bogging down before picking up speed and feels less powerful.
jerks as well during foot of gas deceleration.

 

[cerbomark]

Do you have an easy way to temporarily put the stock tune back in? I d see if it does It then and that could narrow down the issue if it s only on the tune map.
Doubt it is the plugs in your situation .

well the coil packs not being touched is good. pull any codes yet?

 

[Leigh_bullitt]

No codes what so ever.
only one that did crop up was “Crank position sensor not learned”.
But this was directly after I did a KAM reset and a crank Relearn on the SCTx4.

 

[cerbomark]

can you put the stock tune back to test?

 

[Leigh_bullitt]

Yeh tried that.
it still behaves in the same way. Runs great then intermittently poor.
I thought it was just me but their is definitely a difference in power and smoothness in the engine

 

[NGOT8R]

Have you inspected the air filter, MAF sensor and throttle body and cleaned them if necessary?

 

[Traffic22]

If it’s bogging and stumbling, it almost sounds like unmetered air is getting in….check for a vacuum leak and check the intake tube to make sure no small cuts or tears in it. If there is a tear past the MAF when the engine moves that hole may open and let air in which would explain the intermittent nature.

 

[Leigh_bullitt]

Good Point.
I’ll take a look.
On the scan tool at idle
AFR is reading 1.00
Lambda 1 and 2 - between 1.00 - 1.09
Spark advance : 10-14 degrees

 

[Leigh_bullitt]

Short term - 1.00%
long term - 0,92%

 

[Mustang_Lou]

This may be a dealer-visit situation.

 

[Snellemin]

So I got my Bullitt used and had something similar happen to mine. It got worst and narrowed it down to the actual connector to the throttle body. I bought a bunch of connectors and none fitted right. Found a connector from an F150 that fit perfectly and never had the issue again.

So just check the connector and remove the throttle body to check the seal behind it. And as mentioned before, check for cracks in the intake tube behind the MAF sensor. Hopefully it's something that simple.

 

[Leigh_bullitt]

So I got my Bullitt used and had something similar happen to mine. It got worst and narrowed it down to the actual connector to the throttle body. I bought a bunch of connectors and none fitted right. Found a connector from an F150 that fit perfectly and never had the issue again.

So just check the connector and remove the throttle body to check the seal behind it. And as mentioned before, check for cracks in the intake tube behind the MAF sensor. Hopefully it's something that simple.

Cheers
Yeh I’ll take a look.
It’s definitely something relating to the throttle body that’s for sure but weird how it’s so intermittent. That probably rules out a leak and probably something more electrical.
I’ll try and pull the battery and see if that helps.
maybe it’s something simple like a reset.

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