I believe that there is a reset switch/button behind the panel on the front passenger side where you turn off the air suspension. Down where the front passengers feet would be. you will have to take off the plastic door step (has the Lincoln symbol on it) in order to take that panel off... You can pop the door step off with a flathead screw driver...
No the gage has no effect on firing. An engine that is overheating will misfire.
5W-30 ( according to the 1998 Lincoln Navigator Owner Guide )
On a 1998 Lincoln Navigator : The thread on cap on the engine coolant reservoir is the pressure cap / radiator cap
According to the 1998 Lincoln Navigator Owner Guide : ( " regular " unleaded , 87 octane gasoline is used )
On a 1998 Lincoln Navigator : The ELECTRIC fuel pump is INSIDE the fuel tank ( it goes in from the top side of the tank )
On a 1998 Lincoln Navigator I believe it is in the front passenger footwell ( it might be behind an access panel )
I tried all the tricks of backing up and putting it in neutral and park and other things but finally I disconnected the battery and it reset the system. worked for me on my 1998 navigator.
You can view the 1998 Lincoln Navigator Owner Guide online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides
6x9's
According to the 1998 Lincoln Navigator Owner Guide : ( 5W-30 , 6.0 U.S. quarts with engine oil filter change )
According to the 1998 Lincoln Navigator Owner Guide : With engine oil filter change : ( 6.0 U.S. quarts )
According to the 1998 Lincoln Navigator Owner Guide : ( 30 U.S. gallons )