More car woes. /sigh

Having just fixed the VID block problem on my car, I took it for a test run in the mountains. Car runs well and the new TCM firmware helped smoothen out the jerky 1-2 shift. An early morning run on mountain roads won't need A/C so I drove with the windows down. It was then when I noticed a metallic rattling sound from my engine under load at low revs (~1500 RPM). The sound goes away once the car gets going though. What could be making that noise? My engine is a 1.8 Duratec HE, btw.

In addition, during that same run, I came across a speed bump that was not marked. I hit the brakes hard to slow down before the bump, but I still ran over it at a fairly fast speed. After the hard braking and the jolt, my brake pedal sank halfway to the floor. Made me panic a little bit. xD

The brakes still work great, but the pedal travel changed drastically. If I step on it like I normally would, it would just bite a little, then sink down until I get pressure again. It's important to note that this has happened before, and we replaced the brake master cylinder to cure the problem. It's barely been a month since we did the replacement and my brakes are acting up again. Will we need to replace the master cylinder again, or is there something else that we should look at?

Does the car have ABS? If so did you also bleed the ABS pump after replacing the master cilinder? If not there is a big chance that air got trapped inside the ABS pump. This air can not be removed by bleeding the brakes normally. The ABS pump needs to be bled softwarematically using a suitable (Ford specific) diagnostic system.

Personally I would start with bleeding the brake system and the ABS pump.

We bled the brake lines at the master cylinder after installing it. We also bled the lines going to each wheel a few hours ago in the hope of making the brake pedal firm up. No bubbles, so no air in my brake lines.

It does have ABS, yes. Makes sense, come to think of it. The pedal issues happen after hard braking (which probably means master cylinder we replaced wasn't broken after all). No idea though on how to bleed the ABS with just the tools in our home garage. Any way of doing the ABS Pump bleed without special tools?

The ABS pump can only be bled softwarematically with a suitable diagnostic system. To bleed the ABS pump the pump valves must be opened in a certain sequence and the pump motor must be activated to pump all air out of the ABS unit.

isn't there an ABS bleed function on forscan

ForScan doesn't have the ABS bleed function on my model. I guess it's a trip to the suspension & brake shop soon.

What about the rattling noise from the engine I hear? Could it be the timing chain or loose valves?

After 3 days in the nearby Ford service center, the car's brakes still haven't firmed up. They charged me for a ton of brake fluid and a "diagnostic fee" that I insisted that they waive. We pulled the car out because they've replaced all the brake fluid twice (for a reason that escapes me).

Either there's something really wrong with my brakes, or the service people have no idea how to perform the ABS bleed.