Had a 98 with same prob. Check MAF sensor
Sometimes when a car over heats and it is really warm outside your car will not start due to " vapor lock "
Rev limiter
This has happend to me a couple off times.First time was because of a bad battery connection.The second time was a bad starter solenoid.
how many miles on this puppy? there known for fuel pumps but if it seems to be turning over faster than usual it could be the timing belt
Does it turn over? Is it getting fuel, spark, and compression?
The 1999 Mercury Mystique wiper blade sizes are 22" drivers and 20" passenger side wiper blades. See Sources and Related Links below for more information. Since there are over 22 different wiper arm attachments, do not buy wipers just by length only. Be sure to lookup exact wiper blade part numbers by vehicle make, model and year for the brand wiper you decide to purchase. This ensures correct length AND correct attachment.
I had the same problem on my 1996 Pontiac firebird, they told me that my ignition cylinder had went out. Maybe you could ask about that, I don't know what would cause that to go out though? I had a similar problem 1998 Mystique LS. It was a burnt out relay. Also the ignition switch (what the key turns on...I'm not a mechanic I think that is what it was called) was worn and I had to replace switch.
The 1999 Mercury Mountaineer either has the ( 4.0 liter Single Over Head Cam , V6 engine or the 5.0 liter V8 , which is an over head valve / pushrod design engine ) Helpfull
In a 1999 Mercury Mountaineer : Either the 4.0 liter Single Over Head Cam ( SOHC ) V6 engine , or the 5.0 liter V8 , which is an over head valve / push rod design engine
1988 cougar will not crank over
Pump, fuse, or fuel pump relay.
The engines in a 1999 Mercury Mountaineer ( 4.0L Single Over Head Cam V6 and the 5.0L Over Head Valve V8 ) are both fuel injected , so there is no carburetor