Loss of power/Jerky acceleration

[LePhatnom]

Car is booked in next week for Ford to take a look, but I am curious if anyone has an idea of what may be going on

Jerky acceleration occurs around 1500RPM and up. It feels like car is jolting forward and back, sort of like stepping on gas and releasing at a very low gear.

Happens probably once every 3-4 times I accelerate

I might be imagining it but when I give it a lot of gas, I feel like the car is also accelerating slower than it should

Its only gone 8000km and I dont think it is the fuel as I have refueled twice since it started

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[LePhatnom]

So after two weeks of not knowing what it was. First replacing parts as a process of elimination, then draining and replacing the fuel, now they finally say they found damaged spark plugs. On the phone they said they reckon it could be from poor fuel quality.

I shouldn't buy that should I? They want me to pay $200 ish to replace plugs. I feel like I should stand ground and push for warranty and proof that it is was the fuel.

 

[msweet]

What fuel are you putting in it? and where from?

 

[Burkey]

I strongly doubt that poor fuel would cause the issue with the plugs.
Are they referring to low octane OR debris?

 

[LePhatnom]

They were not specific but I will be in tomorrow to talk face to face regarding the plugs.
The car has only ever received 98 octane from PUMA (BP)

 

[PKs]

They were not specific but I will be in tomorrow to talk face to face regarding the plugs.
The car has only ever received 98 octane from PUMA (BP)

I have a feeling that Puma is not BP fuel. I have had problems with poor running in cars in the past and was advised to use BP. Problem gone and have used BP since.

 

[LePhatnom]

I have a feeling that Puma is not BP fuel. I have had problems with poor running in cars in the past and was advised to use BP. Problem gone and have used BP since.

I think your right. I think PUMA just bought the old BP stations. Problem is that there are no other suppliers of 98 here except for PUMA and one BP station really far away. Ill give that BP a go

 

[Burkey]

They were not specific but I will be in tomorrow to talk face to face regarding the plugs.
The car has only ever received 98 octane from PUMA (BP)

So, let’s assume for one moment that octane is fine.
If there was sediment in the fuel, I would tend to think the injectors would typically give up well before the plugs do.
Could be wrong. :shrug:

 

[Aus-MustangGT]

So, let’s assume for one moment that octane is fine.
If there was sediment in the fuel, I would tend to think the injectors would typically give up well before the plugs do.
Could be wrong. :shrug:

Burkey you know Ford doesn't use logic or any form of intelligence like that. You are 100% right though. Fuel passes through a few places before the spark plugs

 

[Aus-MustangGT]

They were not specific but I will be in tomorrow to talk face to face regarding the plugs.
The car has only ever received 98 octane from PUMA (BP)

Puma don't use BP fuel, they use S-Oil based fuel and change their additives once here. Either way 98 shouldn't be fouling your spark plugs

Push back on Ford because you followed the manual and filled up 98 octane only. I'm no tuning expert but one 'bad' tank isn't going to. Be enough to foul spark plugs

 

[Burkey]

Burkey you know Ford doesn't use logic or any form of intelligence like that. You are 100% right though. Fuel passes through a few places before the spark plugs

Yeah my bad...:lol:
Seriously, there’s a MUCH better chance that the plugs were either faulty from the get go OR incorrectly gapped.
On the bright side, plugs are cheap*

*except when purchased from a Ford dealer :headbonk:

 

[LePhatnom]

Got some further details today

The misfires are completely random. Compression tests are normal. Coils were changed without any improvement
The spark plugs that were taken out had a brownish coating over it
Their basis for poor quality fuel was basically a sniff test. 98 should be pungent and burning to the nose etc, but it wasnt. I called bullshit on that because even it was slightly lower, the car can run on 95 and even 91 without issues (According to the manual). And if it was properly off, shouldn't it smell like paint stripper?

So now just waiting on new plugs

 

[Burkey]

Got some further details today

The misfires are completely random. Compression tests are normal. Coils were changed without any improvement
The spark plugs that were taken out had a brownish coating over it
Their basis for poor quality fuel was basically a sniff test. 98 should be pungent and burning to the nose etc, but it wasnt. I called bullshit on that because even it was slightly lower, the car can run on 95 and even 91 without issues (According to the manual). And if it was properly off, shouldn't it smell like paint stripper?

So now just waiting on new plugs

Honestly, I think you’d need a pretty bad tank of fuel.
More importantly, if that was their suspicion, wouldn’t draining the tank and refilling be the first course of action?
I’m not a mechanic, but in the interests of the KISS principle it would seem a good place to start.
Also, there’s always the old cracked IM (not unheard of on this platform) and the old broken CMCV, as per this video...

 

[LePhatnom]

They reckon they finally found the problem
Spark plugs did nothing so they looked further into the engine and found a small piece of metal inside the engine bore.
Asked me a few questions about mods (none), and they just set it off to ford australia

 

[Burkey]

They reckon they finally found the problem
Spark plugs did nothing so they looked further into the engine and found a small piece of metal inside the engine bore.
Asked me a few questions about mods (none), and they just set it off to ford australia

I hate to say it, but this can’t be good.
I really hope they’re doing compression tests and all the rest of it right now.
Could be wrong but I seem to recall another member (Aussie) having a similar issue.
I don’t recall the specifics but I’m pretty sure he ended up with a new engine.

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