What could cause the temperature gauge to fluctuate?

I put key in ignition this morning, temp gauge fluctuated went right into the red then back down and back to red about 5 times. Started engine continued to bounce around even while driving

I took coolant cap off but it still fluctuated. It did this for a while last year but stopped for a while but then I noticed it fluctuating again today.

car is a ford focus 2006 mk2 sport 1.8 tdci

any ideas to the cause?

thanks

Added (1). Is it possible a crack in the head or engine block could be the cause?

Added (2). It happens after I get in my car after it has been parked a while such as over night and put the key in the ignition, before I even start the engine it fluctuates, and often continues to fluctuate after starting the engine

2001 Ford Focus ZX3 Starter Won't Turn Engine?

So, I'm driving down the street away from my house in my Automatic 01 Focus ZX3, I have to let the idle settle down to the standard 650 RPM before I pull out due to a vacuum leak likely (not the actual problem here).

As I came up to the first stop sign at the end of the street, and I see a battery light, the first thing I assumed was the serpentine belt slipped off (it had previously before I replaced the idler pully)

But then I realize before the car fully stopped that the engine itself was no longer running, I stop and try to restart the engine, and the starter spins up as if the flywheel is not engaging.

I ended up replacing the starter, and the problem was not fixed. Same thing, the engine is not being turned by the starter. No compression of resistance, just the sound of the electric starter spooling up.

I even tried another battery (the one I currently have looked to be in bad condition) no difference.

What in the world could this possibly be?!

Connections are good, starter runs strong and no apparent electrical problems.

Could it be a bad relay?

Any help would be great, thank you.

2009 Ford Focus SE High Idle RPMs?

I have a 2009 Ford Focus SE 4 Door Sedan, Automatic Transmission, 135, xxx miles, no accidents very well maintained.

All was fine until two weeks ago when the idle RPMs started changing. Currently, when the car is initially started (either after being outside or stored in the garage over night) the idle RPMs are around 1500-1700.

That idle speed holds firm until I out the car in drive, neutral or reverse - regardless of how long I let it idle for.

The temperature has ranged between 15 degrees farenheit to 40 degrees farenheit.

The car was not doing this last winter.

There's also a noticeable ticking sound which may be the timing belt?

Could anyome provide insight into the high idle? Such as whether this could be a timing belt issue, transmisson issue, sensor, etc?

My tires in car keep going flat

Just bought a 2014 ford focus in December. Love it. Last week, i got a flat in the front passenger one. Got a new tire, drove great for a few days. Today, the light went on indicating that the pressure was low, but in a different tire. Stopped at a gas station, had them fill them up, light went off, drove home fine. Now i go outside a few hours later to run to the store and the tire is flat!

Added (1). There's no holes in the tire once my mechanic looks at it.

High pitched beeping sound inside dashboard?

I have a 2012 Ford Focus. For the past month or so, every single time I turn on the car, a loud, persistent beep will go off for 16 times. 16 times exactly, then it will shut off and not happen again until I turn on my car again. Sometimes it won't happen, but only if the car has been turned off and on again within a 2 or 3 minute time span. What is this?

Break line repair cost for a 2001 Ford Focus

The break light on my Focus lit on and the peddle has like no pressure. I'll go to 5 mph, hit the breaks and it'll be a full second between me pressing all the way down and the car actually stopping. Similar situation with my mom's 03 Sonata some years back.

I'm pretty sure it's both break lines that need to be repaired and I know I can't do it myself. How much would a mechanic charge for this? I know parts can be inexpensive, but labor can be pricey.

Normally I'd call one, but I work all night and it'll be several hours before I can call for an estimate, let alone a tow.

Why is my engine sluggish when hot for a while?

2003 Ford Focus.
When I drive for more than a half hour on a hot day, the engine will be sluggish and misfire while under load. I have checked several components and I suspect that the problem is either the fuel injectors or the spark plug wires.

Car vibration on acceleration?

I have a Ford Focus 1.8 TDCI 2007 and whole car vibrates while acceleration at certain speeds say above 40mph. Car coasts fine so issue is only when gear is engaged and on acceleration.

I took the car to few garages they came with different things like Fuel filter, Injectors, Dual mass flywheel + clutch, Driveshaft in no particular order.

Sadly, all these repairs would exceed the value of car so need some expert advice.

I'm relying on you guys, thanks in advance.

Added (1). Update:
Bushes look worn out however this should make car vibrate all the time.
New engine mount
Drop link is good
Front wheels spins fine
Drive shaft doesn't make any noise when slightly moved using an iron bar.
Gears move freely
Clutch is smooth and no grinding noise, clicking sounds
2 injectors leaking however injector specialist confirm that should cause vibration

Car has power and I can drive through this shake/vibration.

Added (2). No engine management lights
Injector specialist confirmed issue not due to injectors.

Added (3). No engine management lights
Injector specialist confirmed the issue is not due to injectors.