2000 Mercury Mystique - Answered Questions & Fixed issues

Check the temp sending unit. That is what tells the gauge to move.

It should be in the valve cover. https://www.google.com/search?q=PCV+valve+on+a+2000+Mercury+Mystique&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjQpOyh8ZXSAhULr1QKHWzkAaAQsAQIOg&biw=1920&bih=960

Have the power brake booster checked, it may have a vacuum leak in the booster diaphragm or a defective brake booster vacuum check valve.

Sounds like a cracked cylinder head or head gasket problem

Sounds like a throttle body issue or idle valve problem. I would clean the throttle plate and idle valve

When not running the brakes will be hard when pressed on. Will it not crank over at all ?

Well, a "bad" fuel filter is unlikely to be the cause of your issues. Fuel pump, more likely. It's in the tank, so it's not a quick DIY job to replace. You may be able to jump start it with help from another car, but if the fuel pump is bad, it won't stay started. You may have to tow it to a repair place.

that indicates a transmission problem, scan for codes to determine what kind of problem is occurring

Bad ground wires.

Travis, this Mystique has sealed wheel bearings, you do not pack them with grease. You cannot even access the bearing. If you are not familiar with a car, you do not know if you are giving correct directions or not.

CHECK THE OWNER'S MANUAL IN SECTION ; 'BATTERY REPLACEMENT'. DISCONNECT THE POSITIVE LEAD FROM THE BATTERY, WAIT FOR 10 MINUTES AND RECONNECT IT. FOLLOW THE STEPS AS FOR A NEW BATTERY FROM THE MANUAL.

If it's a manual transmission,then maybe your clutch slave cylinder is bad,check your clutch fluid reservoir,if empty then it's bad and needs replacing,should have fluid around it.Here's a link to replacing your clutch slave cylinder. SAVE 20 ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE Here's a picture of the part. Clutch Slave Cylinder at AutoZone com Best Clutch Slave Cylinder Parts for... Also check your master cylinder,could be bad.Here's a link to the part. Clutch Master Cylinder at AutoZone com Best Clutch Master Cylinder Parts... Here's how to replace the clutch master cylinder. SAVE 20 ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE And lets not forget to bleed it,here's a link for that. SAVE 20 ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE The brakes and clutch share the same reservoir.The end....

I would only sugest using replacement line no substitute. They are as expensive as some may think and will save u a lot of time, not to mention safety first.

bleed the spliter vale out uderneath car near back

What does the feul pump operate?

Here's a link on how to replace your belt. http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0996b43f802e5d6a

is mounted on the fuel rail under the intake manifold

Theft light staying on?

Goodness, it sounds like you have too many electrical issues to be able to solve them in a few paragraphs. I would suggest, if you have the time and desire to track this down and fix it, your best bet would be to go get a Chilton's manual for your make and model. It has electrical diagrams and such in the book. It has all kinds of info you may find useful as you worth through your problems.

Easy fix, replace your temperature sensor. Its located on the thermostat housing or on the radiator itself. This should fix this problem because its stuck open.