What is this?
 

Hey, I was just washing my engine compartment the other day and I noticed something and didn't know what it was or what it does. Can anyone tell me after looking at the picture?

Mine had what appeared to be a very light coating of oil on the top part of it, is this anything to be concerned about?

***ALSO***
This is off topic, but also VERY important to know.

Awhile back I took my car to the dragstrip (Bandimere), and after a fair pass of 14.9 I get off the gas to get on the brake. What happened next freaked me out big time. When I got off the gas, the engine shut off. Turning off my power steering and everything. That could've caused a big problem at 90+mph. So I restarted the car and it started right up, idled low when I slowed down, but ran fine getting back to my pit. On my second pass of 15.9 I didn't hammer the throttle all of the way, and she ran comfortably, but when I go to touch the brakes, her rpms dropped BIG TIME. So I decided to take her home. After letting her rest for two or so hours I get back on the highway, and she's running great and sounds healthy for about 3 1/2 4 miles and she dies.

That was back in the latter parts of May and it hasn't happened again since.
What could cause this? Or better yet, how can I prevent this from happening again?


Thanks

Beats me dude, but it is nice to see another Colorado guy on here. I live about 5 min from bandimere.

im sure somone on here will be able to help ya out.

That's got to be fun. I live 5 mins from Boulder, so it's quite the drive for me. Do you go down for test and tunes?

lol. actually no ive never ran it up there.

Not big on the whole racing honestly, i just like having a kickass car. lol

Thats the brake booster (I think). I know it has to do with the brakes. The automatic mustangs have huge cylindrical box brake booster, manuals have that thing in the picture. I don't know why there is a difference.

My car is a 2004 Mach 1 with a manual t3650 trans, JLT intake, and Magnaflow exhaust. So the mods wouldn't cause this, would it?

And what's could have caused it to leak? It's nothing major, so is it anything to be concerned about?

Its the hydroboost aka the power brake booster. It doesn't run off vacuum from the motor like the older cars do (i believe 01+ are all hydroboost) instead it uses power steering pressure from the power steering pump to pressurize the brakes up. If its leaking then your loosing power steering fluid or brake fluid. I would believe its only power steering fluid though as I don't believe brake fluid ever goes in there. I would have to double check that.

Does anyone know what might have caused it to die? It seemed like got it going fast, it'd die when I hit the brakes. Should I keep it in gear while I'm decelerating? Because how I did it then was I'd put her in neutral and then get on the brakes. I used to race like that with my old 3.8, but that was my first time in the 4.6. Do you think keeping her in gear might help?

+1

How do you know its dead, I just thought you needed to know what it is?

my mach did that to me once, after having a little fun i pulled out of the lot and when shifting from third to neutral to come to a stop light my car died. i had to fight it into the nearest pullover. hasn't happened since

It was two separate questions.
#1 What is that thing? (got the answer)
#2 Why did my car die? (refer to post #1)

Mine didn't fight me, it would turn back on immediately and run healthy. It just happens when I'm really on the throttle and then I get off. Last time it happened was when I was running on an open road near my location and I must have been going 85 or so, I wasn't really "on the throttle" like I was the time before, but I was comfortably in fourth, then I thought I should save some fuel so I put her in fifth and not 10 seconds later, she's dead. I just want to make sure that I find a solution to this problem before I take her back to the drag strip during Labor Day weekend.