2018 GT Premium Engine Problem

[DukeGaGa]

Pretty easy test, swap back out the spacer and see if it resolves the issue. Ensure the sensor on the intake is installed and orientated correctly (shouldn't be able to install improperly, but double check).

Was the intake changed, or was the Air spacer the only thing added?

That's what we'll be doing today, removing the spacer. The sensor wasn't removed from the tube, so the direction didn't change, just unplugged so the cable won't get in the way. I swapped my sensor with it but it didn't help, so it shouldn't be it.

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[Anthony 05 GT]

If you took the intake off and didn't install new gaskets you screwed up big time . NOT covered under warranty :doh:

Intake gaskets are silicone rubber and be reused multiple times.

 

[cosmo]

That's what we'll be doing today, removing the spacer. The sensor wasn't removed from the tube, so the direction didn't change, just unplugged so the cable won't get in the way. I swapped my sensor with it but it didn't help, so it shouldn't be it.

When removing the airbox did you have to remove a groundstrap from somewhere? Was it reinstalled?
Check the gasket wasn't damaged
Check to ensure you didn't over tighten throttle body and cause a hairline crack (spacer is behind the throttle body, correct?)
Was the pcv system properly reconnected?

 

[DukeGaGa]

When removing the airbox did you have to remove a groundstrap from somewhere? Was it reinstalled?
Check the gasket wasn't damaged
Check to ensure you didn't over tighten throttle body and cause a hairline crack (spacer is behind the throttle body, correct?)
Was the pcv system properly reconnected?

Not sure what you mean by groundstrap (wire that connects to the car chassis for grounding?), but there's nothing connected to the airbox other than the MAF sensor on the tube. The throttle body was tightened to 89 in-lbs. Will check the gasket for the spacer today after removing it, don't think there are any other gaskets involved. And pcv system is properly connected (didn't take them off in the first place but did disconnect them and plug it back in to make sure yesterday).

 

[DickR]

Since everything was fine prior to the removal/reinstall of the air intake stuff I would triple check for ANY wire or hose that might have been bumped/stretched/broken/disconnected/kinked/not fully seated/etc. during that process. You might even check silly stuff like is the dipstick fully seated. Basically anything which may have been disturbed by hands/arms/elbows/etc. Also try disconnecting whatever lighting was installed and/or check to make sure any connections which were loosened were tightened. Make sure no terminals were shorted.

Rule #1. If it worked before I touched it and is broken after then I probably did something. Easy to say, not always easy to find. Speaking from experience.

For example: We had a shop replace the A/C condenser on our 97 Mustang. Car wouldn't start for them afterwards. One of their guys drove to our house to get another PATS key from my wife since I was at work. No luck. Meanwhile I researched everything I could find on the internet and it became clear that they must have disturbed a connector to the PATS computer (separate from the PCM as I recall) that "just happens" to be near the condenser. Their Ford certified tech didn't want to waste anymore of his time so the shop had it towed at their expense across town to a Ford dealer. It was the PATS plug.

Good luck. Also correlation doesn't necessarily mean causation. Just because it happened when you guys were working on the car doesn't mean you actually caused the problem. ;)

 

[DukeGaGa]

Since everything was fine prior to the removal/reinstall of the air intake stuff I would triple check for ANY wire or hose that might have been bumped/stretched/broken/disconnected/kinked/not fully seated/etc. during that process. You might even check silly stuff like is the dipstick fully seated. Basically anything which may have been disturbed by hands/arms/elbows/etc. Also try disconnecting whatever lighting was installed and/or check to make sure any connections which were loosened were tightened. Make sure no terminals were shorted.

Rule #1. If it worked before I touched it and is broken after then I probably did something. Easy to say, not always easy to find. Speaking from experience.

For example: We had a shop replace the A/C condenser on our 97 Mustang. Car wouldn't start for them afterwards. One of their guys drove to our house to get another PATS key from my wife since I was at work. No luck. Meanwhile I researched everything I could find on the internet and it became clear that they must have disturbed a connector to the PATS computer (separate from the PCM as I recall) that "just happens" to be near the condenser. Their Ford certified tech didn't want to waste anymore of his time so the shop had it towed at their expense across town to a Ford dealer. It was the PATS plug.

Good luck. Also correlation doesn't necessarily mean causation. Just because it happened when you guys were working on the car doesn't mean you actually caused the problem. ;)

Thanks for the advise. I've checked everything that might got disconnected or loose during the installation, but nothing helped. The dealership said the latest they'll be able to work on the car is Thursday, but probably Wednesday, so we should know what's wrong with it soon enough. Right now I'm guessing something went wrong with the fuel pump, since it's random cylinder misfire and the chance of multiple injector or spark plugs going bad is pretty low I'd imaging, I've also seen a video saying his intake manifold has some rod broken, but that's a physical break down and new parts don't tend to do that, most likely something electrical.

 

[Redbarn Mustang]

Make sure there are no leaks between the mass air flow sensor and the throttle body(loose clamp, tear in the boot etc.) I've seen it a million times, not on mustangs but other cars.
Did you wash the engine? I've seen water in the plug holes before causing a skip and not setting the check engine light on for a while.

 

[Cobra Jet]

There’s been a few completely stock 2018 GT Owners posting in the TSB sub forum on here of failed valve springs ... not saying that’s the case since that’s the furthest possibility from playing with the air box assembly and throttle body... but.... just putting it out there.

EDIT:
CORRECTION... I didn’t realize of the prior mis type in model year, until reading here now, meant to put in 2017, not 2018... sorry for any confusion!!!

 

[GNN60GT500]

There’s been a few completely stock 2018 GT Owners posting in the TSB sub forum on here of failed valve springs ... not saying that’s the case since that’s the furthest possibility from playing with the air box assembly and throttle body... but.... just putting it out there.

Links? I've only seen 15 to 17 owners posting valve spring issues

 

[WildHorse]

Also, if it is, the spacer would have caused the leak when it was installed, not after two weeks.

You bet it would if you didn't torque it down properly.

 

[DukeGaGa]

There’s been a few completely stock 2018 GT Owners posting in the TSB sub forum on here of failed valve springs ... not saying that’s the case since that’s the furthest possibility from playing with the air box assembly and throttle body... but.... just putting it out there.

Hmm, interesting. Will check it out in a bit.

Make sure there are no leaks between the mass air flow sensor and the throttle body(loose clamp, tear in the boot etc.) I've seen it a million times, not on mustangs but other cars.
Did you wash the engine? I've seen water in the plug holes before causing a skip and not setting the check engine light on for a while.

Yep, checked, no problems there.

Also, update on the throttl body spacer, removes it so everything is back to stock, still misfiring.

 

[emcee1011]

Could be a big coincidence? I see a few recent posts here mentioning misfires on stock mustangs.

 

[Blown_90LX]

This is the most ridiculous post ever. We tore a bunch of stuff apart that have to do with air metering, such as the MAF, the vacuum registers low after screwing with a metered air point at the throttle body, but it’s Fords fault and has nothing to do with my handiwork.

Come on man, reread your own description and ask yourself what the real cause is.

I agree with whoever said they would have chosen a different title for this post.

 

[DukeGaGa]

This is the most ridiculous post ever. We tore a bunch of stuff apart that have to do with air metering, such as the MAF, the vacuum registers low after screwing with a metered air point at the throttle body, but it’s Fords fault and has nothing to do with my handiwork.

Come on man, reread your own description and ask yourself what the real cause is.

I agree with whoever said they would have chosen a different title for this post.

I think you should be saying that to yourself. Have you even read the original post? I'm stating what happened, and nothing else. All I'm saying is we were doing mods, and just so happen that the engine started to misfire after we put everything back together. Through out the post I said one thing, I don't believe it's something we've done that caused it to break, but all we can do is speculate since, and again, we did not touch anything that is related to the problem. But just to be safe, we removed everything we put on there. Read and think before you post, thank you, but no thank you.

 

[DukeGaGa]

Could be a big coincidence? I see a few recent posts here mentioning misfires on stock mustangs.

This is what I'm thinking right now, but we shall know soon enough, tomorrow the car will be towed to the dealership and hopefully we'll get some results soon after that.

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