Hi there so I have a 2005 Ford Mustang GT with aftermarket Ford K springs, A Strut Tower Brace, a Whiteline Adjustable Panhard Bar and Lastly Roush Extreme Axle Backs.
Car has about 47k miles and hasn't brought me any problems in the past.

So here is what's going on, whenever I am in gear or at least when the vehicle is moving and I accelerate a odd noise occurs mainly immediately after I accelerate. It started to happen after I did some yard work for my mother and drove (20 or so miles home) and I hadn't noticed it until the next day (Happened about 2 day ago.) it's more noticeable around 3k and then letting off the throttle and seems to go away after about 35 to 40 mph...
Also this only plays up to 3rd gear, can't tell if the same effect is present in the 4th gear with the low speed or wind noise

To explain what the noise sounds like... To put it bluntly it's like something is shifting in place, like a stuck metal plate wedging into place (Bearing?) for .5 - 1 second after accelerating, my theories were either the VCT as the car is acting odd at low rpm and is making a noticeably louder ticking noise (may just be injectors and me freaking out), which could be an exhaust leak possibly.

Also! I do believe this all happened after I did the yard work because after I had finished doing the yard work for a little extra money I got some gas at a shell, 87 octane here in CO so Premium for us. So I am also worried I've ran around 40-50 miles of potentially contaminated fuel or probably more likely got my fuel contaminated?

 

So I’ve tried checking several possible candidates as well as recently change spark plus’s at 47k miles for the first time...

lifted the front and checked the front left bearing seems to have some noise but nothing too serious. The covers for the exhaust are tight. The noise seems to randomly come from the engine, it isn’t always there when you’re idling it deferentially sounds like metal rattling like the exhaust but it’s coming from the engine or pulleys to my ear...

The specific sound sounds more like you have a deck your flipping through.

also I decided to upload a video to help illustrate my point.

any suggestions would be great thanks!

 

Sadly I can't hear anything ticking. 87 is not premium in CO, 91 is but that shouldn't make a difference if you don't have an aftermarket tune as Ford GT Mustangs are designed to run on just about anything although premium is recommended. Try putting premium back in it and see if it goes away.

 

The 2005 does not have the knock sensors to adjust for octane. It is designed to run on 87 and premium makes no difference without a tune.

 

So at work I decided to unplug the VCT sensors and everything is running like normal, so at least I rounded it down to two things, the cam phasers, and three solenoid, but car has no odd sounds after pulling those not really sure what happened but we’ll see later this week when I get can those two new solenoids

 

VCT controls the cam phasers themselves. You could have play in the Phasers. Very common on the first year or two of the S197 mustang.

This is the replacement process.