Rattling noise on decel and startup

[hope5oh]

Hello guys,

I have a 2018 Ford Mustang GT PP1 with 42k miles and recently started making rattling noise. I first noticed it after starting my car, I hear a snap or a rattling noise but only happens half of the time. I also realized that it makes an identical noise during 1000-1500 rpm rev's on decel. Started to hear and feel loud thuds as well when shifting from P to D or P to R or vice versa (R to P, D to P) Downshifts have become jerky as well and there were 2 rare occassions car would have a rough idle on traffic stop.

Took it to Ford and they ended up charging me for a reflash on the PCM with an attempt of fixing it. Seemed to be less jerky but didnt last a day. Bad startups and the aggressive jerk when downshifting on Sports mode came back.

I have another appointment with Ford next week but I was hoping to hear any suggestions..

I was thinking this could be a bad flexplate hitting the starter or a bad torque convertor but I'm no mechanic so please help.

Link to more videos: https://drive.google.com/drive/folders/1-9KeX4wpzL-umf-j2tlIf0Xcc73woYRv

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[PC_GUARD]

On my phone it sounds like valve train noise..

 

[StangTime]

Sounds like mine. 2019 with 14700km manual transmission.
Consensus is this ratcheting noise is the cam phasers. I also had my oil analyzed and everything was good.

 

[BlackandBlue]

Mine does that. I think mine is actually worse though.

It’s something in the VCT. F150s had a problem with it and Ford did something to fix it. I am sure other know more on that.

 

[PC_GUARD]

It definitely sounds like a chain kind of issue... jmo but absolutely feel it's in the valvetrain

For the dealer to do a relearn makes me think they realize it too

 

[StangTime]

Mine does that. I think mine is actually worse though.

It’s something in the VCT. F150s had a problem with it and Ford did something to fix it. I am sure other know more on that.

That's correct. The fix was only done if it was throwing codes though. In the second video there was no code but the exhaust solenoid for the VCT was making a racket.

Here's some good hands-on info on it.
The problem:


His fix:

 

[hope5oh]

Thanks for everyone's quick reply. So I'm guessing the 1000-1500 ratcheting noise is normal then.. How about my terrible sounding start ups? Here's more videos, most of the time its just a fast clicking noise like the first video I first posted but it also does this in some occassions:

 

[BlackandBlue]

Thanks for everyone's quick reply. So I'm guessing the 1000-1500 ratcheting noise is normal then.. How about my terrible sounding start ups? Here's more videos, most of the time its just a fast clicking noise like the first video I first posted but it also does this in some occassions:

Likely needs a new battery. Have battery tested or put volt meter on it and hit minimum button. Report back with voltage.

 

[hope5oh]

Likely needs a new battery. Have battery tested or put volt meter on it and hit minimum button. Report back with voltage.

battery was just replaced 8/2022. could it be the same problem as this guy? https://www.mustang6g.com/forums/threads/clunking-hitting-sound-on-startup.129340/

 

[BlackandBlue]

battery was just replaced 8/2022. could it be the same problem as this guy? https://www.mustang6g.com/forums/threads/clunking-hitting-sound-on-startup.129340/

If it was just replaced it is most likely not the battery but I always start with the simplest thing and work my way up.

I personally would check battery and battery connections before moving further in the troubleshooting process.

 

[hope5oh]

quick little update:
the rattling noise can be heard on first gear when tapping accelerator in traffic stops.. i was paddle shifting today from a freeway meter and realized that my RPMs struggle to go above 3k-5k both first gear and second gear which is weird, and i coulve swore i was hearing excessive air coming out from the rear but not sure on that.

still getting these problems:
more gas needed to get the car moving than usual, 1-2nd gear struggles to get to high RPM when shifting gears

rapid rattling noise or sometimes just a loud click when starting

in Park rev to about 1500 rpm, on start of decel you'll hear metal rattling or a rapid squealing/whining noise. can also hear in Sports mode paddle shifting in first gear traffic tapping the accelerator

 

[Snakebyte]

I had a similar issue with a different brand car, and finally learned that one of the catalytic converters cracked completely apart around the inlet. Sometimes it generated a code, but most times it did not. It annoyed me for over a year until someone noted that the noise under the hood didn't sound quite right off the left engine bank. Sure enough...replacing the broken-in-two converter pipe fixed the rattles and the infrequent throwing of codes.

 

[hope5oh]

I had a similar issue with a different brand car, and finally learned that one of the catalytic converters cracked completely apart around the inlet. Sometimes it generated a code, but most times it did not. It annoyed me for over a year until someone noted that the noise under the hood didn't sound quite right off the left engine bank. Sure enough...replacing the broken-in-two converter pipe fixed the rattles and the infrequent throwing of codes.

was the car doing the weird startup rattle or loud click as well?

 

[Snakebyte]

was the car doing the weird startup rattle or loud click as well?

Although the noise didn't always occur during startup, in hindsight it occurred more often on cooler mornings. There was a rattle/squeak sound, depending on the temp and engine movement. A rough running cold engine generated more movement but as the engine and catalytic converter warmed up, the sound changed and even went away once both were warm due to expansion of the metals. I purchased my replacement converter from Summit Racing as I recall. Because the mounting bolts were seized, I was unable to leverage them. Therefore I had a local mechanic with a heat induction tool remove/replace the converter for me. His labor was reasonable.

 

[hope5oh]

Although the noise didn't always occur during startup, in hindsight it occurred more often on cooler mornings. There was a rattle/squeak sound, depending on the temp and engine movement. A rough running cold engine generated more movement but as the engine and catalytic converter warmed up, the sound changed and even went away once both were warm due to expansion of the metals. I purchased my replacement converter from Summit Racing as I recall. Because the mounting bolts were seized, I was unable to leverage them. Therefore I had a local mechanic with a heat induction tool remove/replace the converter for me. His labor was reasonable.

sounds like what's happening to me right now, im having ford check it out this coming Monday, thanks for your reply.

was this the sound you were experiencing btw? i managed to get a better sounding video

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