2018 GT Premium Surging

[steve2150]

My 2018 GT Premium with auto and digital dash has been surging on idle and driving, when slowing down for traffic light foot off accelerator even worse. Been using Shell premium, car sat for a few weeks and it started after that. Any ideas.

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[Staimpedance]

My 2018 GT Premium with auto and digital dash has been surging on idle and driving, when slowing down for traffic light foot off accelerator even worse. Been using Shell premium, car sat for a few weeks and it started after that. Any ideas.

How many miles?

 

[steve2150]

1900 miles, gotta drive more

 

[Cobra Jet]

Could be a few things:

1) IMRC plates - known issue of premature failure based on threads in this site - they get replaced under warranty

2) Throttle body (there is a Ford release that some TB’s had to be replaced due to incorrect throttle springs installed at assembly) - gets replaced under warranty.

3) Cracked intake manifold - common on the 5.0 Coyotes based on threads in the 5.0 sub-forum - gets replaced under warranty.

 

[99Zeus99]

Have you screwed with it or is it stock? Tune issues if you have it, are common. Spray some carb cleaner around the intake and you'll find the leak if there is one. It'll surge when it sucks that through the intake.

 

[steve2150]

Have you screwed with it or is it stock? Tune issues if you have it, are common. Spray some carb cleaner around the intake and you'll find the leak if there is one. It'll surge when it sucks that through the intake.

Stock, it is hunting and surging at idle and when slowing down surging. I noticed at idle with hood up the hood prop vibrates and shakes and the engine cover on passenger side also shakes. You definitely can hear the surging from the exhaust.

 

[anmut]

Take it back to the dealership

 

[Zinc03svt]

Stock, it is hunting and surging at idle and when slowing down surging. I noticed at idle with hood up the hood prop vibrates and shakes and the engine cover on passenger side also shakes. You definitely can hear the surging from the exhaust.

I have been going through this since Feb. It finally popped a code under load P0600 and P27B5. Took it to Autozone and it failed voltage regulator 4 out of 6 times. Mine is going in for battery and/or alternator. I also noticed my voltage gauge is jumping all around 12.1 to 14.9 volts while driving.

 

[DetroitMustang]

I have been going through this since Feb. It finally popped a code under load P0600 and P27B5. Took it to Autozone and it failed voltage regulator 4 out of 6 times. Mine is going in for battery and/or alternator. I also noticed my voltage gauge is jumping all around 12.1 to 14.9 volts while driving.

So any updates? I have the same voltage jump from 12 to 14.5. I took it in and they claimed it's in normal range.
Weird how the 1st 10 months it never moved always around 14, but now it's "normal".
When at idle it's 12, also when speeding up at 12, but when slowing down it jumps to 14.5 and back to stop it's 12 again.

 

[steve2150]

Update, a vacuum hose came loose and it was then dumping fuel to cause the surging and hunting. Dealer saw it on their laptop. They were gonna do a smoke test but luckily found the unconnected hose.

 

[Zinc03svt]

So any updates? I have the same voltage jump from 12 to 14.5. I took it in and they claimed it's in normal range.
Weird how the 1st 10 months it never moved always around 14, but now it's "normal".
When at idle it's 12, also when speeding up at 12, but when slowing down it jumps to 14.5 and back to stop it's 12 again.

It has been @ the dealer since Wednesday morning. At first they where going to replace the cam phasers, but Ford has given them a laundry list of things to check first.

 

[Zinc03svt]

Update, a vacuum hose came loose and it was then dumping fuel to cause the surging and hunting. Dealer saw it on their laptop. They were gonna do a smoke test but luckily found the unconnected hose.

Do you know which vacuum hose? I have been all over my pcv connections and intake multiple times making sure everything is connected and tight.

 

[DetroitMustang]

It has been @ the dealer since Wednesday morning. At first they where going to replace the cam phasers, but Ford has given them a laundry list of things to check first.

Well I accidentally found this out today... I started the car and held my foot on the brake waiting for a car to go by. The volt meter was @ 12, but it jumped to 14 and stayed there. Drove to the store, never moved, seemed OK.
I parked the car, when I came out I started w/o holding brake, volt meter went to 12...ughh. So i shut it off, wait for a minute, restart holding the brake again it jumped to 14, stayed there all the way home.
I'm thinking a short somewhere, but the dealer already said it's normal, don't know what I can do. Really weird sh*t.

 

[Zinc03svt]

Well I accidentally found this out today... I started the car and held my foot on the brake waiting for a car to go by. The volt meter was @ 12, but it jumped to 14 and stayed there. Drove to the store, never moved, seemed OK.
I parked the car, when I came out I started w/o holding brake, volt meter went to 12...ughh. So i shut it off, wait for a minute, restart holding the brake again it jumped to 14, stayed there all the way home.
I'm thinking a short somewhere, but the dealer already said it's normal, don't know what I can do. Really weird sh*t.

Got word last night new cam phasers are ordered. Hopefully ready mid week. My voltage does the same, but it checked out as being normal.

 

[DetroitMustang]

Got word last night new cam phasers are ordered. Hopefully ready mid week. My voltage does the same, but it checked out as being normal.

Thanks for the update.. I guess the voltage thing is normal. I've never seen the meter move around like this before on any car that didn't have a bad battery or alternator.
This is gonna make my OCD go crazy..LOL
I'll have to remove that gauge from the dash.
Good luck on your repairs.

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