Engine stutter when aggressively accelerating.

[TyphoonFiST]

Do you have an Accessport or a scantool? Checking fuel pressure also to know LPFP and HPFP output. Also the Low pressure and high pressure fuel sensors.

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[Fiestig]

Did it start somewhat soon after putting gas in? You can get bad gas at times.

You can't have a clogged cat and a lack of backpressure. It would cause nothing but back pressure and you would run terrible 100% of the time if at all.

 

[Shecallzmipapi]

Did it start somewhat soon after putting gas in? You can get bad gas at times.

You can't have a clogged cat and a lack of backpressure. It would cause nothing but back pressure and you would run terrible 100% of the time if at all.

Started day after I took it to a dealership to sell

 

[Shecallzmipapi]

Do you have an Accessport or a scantool? Checking fuel pressure also to know LPFP and HPFP output. Also the Low pressure and high pressure fuel sensors.

Sent from my SM-S908U1 using Tapatalk

I have a scan tool I use. I'll try thar out tomorrow

 

[Shecallzmipapi]

Started day after I took it to a dealership to sell

What would be the symptoms of a clogged cat?

 

[Intuit]

Just replaced spark plugs and ceiling packs today. Ended up needing to replace the whole valve cover and bracket due to ford's aweful engineering lol. But no luck the problem still persists

For the future, avoid running out and installing new parts without testing first.
We call that, "throwing parts at it."
Having had all four coils go bad simultaneously would've been virtually unheard of.
The test for those would've been to use a spark gap tester to compare the performance of each, against one another.
I've located failing coils on my motorcycle using that method.
Sometimes the electrical resistance on primary and/or secondary coils changes but they'd have to be pretty far gone for that to be detected using the millivolts of power that a typical volt meter puts out.

What would be the symptoms of a clogged cat?

Diminished power output as the engine (actually cat) heats up.
Running the engine cold (for years) my previous vehicle gradually clogged the cat.
Eventually I had to floor it to get up a long steep hill and would still be loosing speed.
THere was a lot of white ash in the exhaust header.
The test for that was to simply disconnect the exhaust and go for a drive.
That ash quickly disappeared.
Zoomed up that hill like a champ.
The cat looked like it needed a long bath in some CLR Cleaner.
It was naturally aspirated so there wasn't any missing or anything like that; just had diminished, eventually severely diminished power.

EDIT: Note, it may be possible to burn valve(s) on a performance engine when running with disconnected exhaust.

 

[SteveS]

Have you considered fuel starvation from a clogged fuel filter?

 

[TyphoonFiST]

Have you considered fuel starvation from a clogged fuel filter?

Fuel filter on these is built into the fuel pump itself* whole replacement would be necessary. Which sucks....but could be*

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[Shecallzmipapi]

For the future, avoid running out and installing new parts without testing first.
We call that, "throwing parts at it."
Having had all four coils go bad simultaneously would've been virtually unheard of.
The test for those would've been to use a spark gap tester to compare the performance of each, against one another.
I've located failing coils on my motorcycle using that method.
Sometimes the electrical resistance on primary and/or secondary coils changes but they'd have to be pretty far gone for that to be detected using the millivolts of power that a typical volt meter puts out.


Diminished power output as the engine (actually cat) heats up.
Running the engine cold (for years) my previous vehicle gradually clogged the cat.
Eventually I had to floor it to get up a long steep hill and would still be loosing speed.
THere was a lot of white ash in the exhaust header.
The test for that was to simply disconnect the exhaust and go for a drive.
That ash quickly disappeared.
Zoomed up that hill like a champ.
The cat looked like it needed a long bath in some CLR Cleaner.
It was naturally aspirated so there wasn't any missing or anything like that; just had diminished, eventually severely diminished power.

EDIT: Note, it may be possible to burn valve(s) on a performance engine when running with disconnected exhaust.

The bolts holding the coil pack into the bracket stripped out so I had to replace 2 coilpacks so I just decided to do them all since I had to change the bracket

 

[Shecallzmipapi]

The bolts holding the coil pack into the bracket stripped out so I had to replace 2 coilpacks so I just decided to do them all since I had to change the bracket

Also changed back to oem spark plugs I've been told that could help

 

[Shecallzmipapi]

Fuel filter on these is built into the pump* whole replacement would be necessary. Which sucks....but could be*

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Did look into that and as u say it is a hassle and getting that part is an even bigger hassle so I'm trying other options first

 

[Fiestig]

Also changed back to oem spark plugs I've been told that could help

Only matters if the gap is correct and same on all plugs

 

[Shecallzmipapi]

Update!!! Took apart my air intake to look for oil none found put it back together check engine light cane on with misfire cylinder 1 checked it and nothing looked wrong new coil pack new spark plug. Put it back together and now it runs wonderfully idk what happened but ig it's fixed

 

[TyphoonFiST]

Update!!! Took apart my air intake to look for oil none found put it back together check engine light cane on with misfire cylinder 1 checked it and nothing looked wrong new coil pack new spark plug. Put it back together and now it runs wonderfully idk what happened but ig it's fixed

Weird....but we will take the win!

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[Shecallzmipapi]

Weird....but we will take the win!

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I guess I got lucky thank you gor all your help though bro it's much appreciated!!

 

[4DGC]

So I had the same symptoms as the OP. My story is this, I started with a Mountune AP and tune. Then got 1 step colder Densos and Dizzy stage 1. Followed that with an intercooler upgrade and Dizzy stage 2 and ran that for around 30,000mi. It started feeling a little rough so I got a new set of NGKs a few months ago and gapped them to .28 as stated on Dizzy's website with a gapping tool. I did not use the bang method. This ran fine for a few weeks then started chugging, bogging, jerking under hard acceleration but ran fine at light throttle. Then the problem went away for about 1,200 miles during which time I took a road trip so that was only a couple weeks. Then it came back and was getting worse and worse. Uninstalled AP, no change. Back to stock Motorcraft plugs and boom, no more problems. Maybe I got a bad NGK? I reinstalled my AP and Mountune tune since it works with stock plugs and it is running strong. I'm gonna run this for a little while and then I'm going back to Denso and Dizzy stage 2 where is was happy for 30k.

 

[Fiestig]

So I had the same symptoms as the OP. My story is this, I started with a Mountune AP and tune. Then got 1 step colder Densos and Dizzy stage 1. Followed that with an intercooler upgrade and Dizzy stage 2 and ran that for around 30,000mi. It started feeling a little rough so I got a new set of NGKs a few months ago and gapped them to .28 as stated on Dizzy's website with a gapping tool. I did not use the bang method. This ran fine for a few weeks then started chugging, bogging, jerking under hard acceleration but ran fine at light throttle. Then the problem went away for about 1,200 miles during which time I took a road trip so that was only a couple weeks. Then it came back and was getting worse and worse. Uninstalled AP, no change. Back to stock Motorcraft plugs and boom, no more problems. Maybe I got a bad NGK? I reinstalled my AP and Mountune tune since it works with stock plugs and it is running strong. I'm gonna run this for a little while and then I'm going back to Denso and Dizzy stage 2 where is was happy for 30k.

Did you check your stock plug gap vs the ngk at .28? Even if Dizzys states 0.28 I would incrementally try a smaller gap. When I had similar issues, it would be intermittent and gave you a sense of no rhyme or reason for the issue. However you have to remember that there is still a level of ecu correction for different scenarios.

Are your NGKs Iridium or Ruthenium? Iridium gap can degrade over time, but is slight. Ruthenium seems to stay true throughout

 

[4DGC]

They were Iridium. I didn't check the gap after I pulled them. I looked them over and didn't see anything telling. They were consistent across all cylinders. I just tossed them once I confirmed the car was running on the Motorcrafts. I was so happy to have my little rocket back that I just didn't care.

 

[Intuit]

Plugs were probably too cold.

 

[Fiestig]

Plugs were probably too cold.

Not too sure about that, but possible. I run step colder with stock turbo and custom piggyback with no issues since getting gap correct.