i need help!

[mogie_bearrr]

i have a 1991 for ranger. its missing and the check engine light is on, how do i read the error code?

 

[RonD]

Have a read here: http://www.therangerstation.com/tech_library/OBD_I.shtml

What engine is in that 1991?
Trans?
4x4 or 4x2?

 

[mogie_bearrr]

It has the 4.0, automatic transmission, 4x4

 

[RonD]

4.0l can be hard on spark plugs, so could just be a bad plug if it is a steady miss.
Use Motorcraft or Autolite spark plugs, 4.0l tends to burn out other brands.

Trouble code will help ID other problems but don't start replacing sensors or parts because of a code.
A code usually means the sensors are WORKING and saw a problem and reported it.
Replacing a sensor is like "shooting the messenger".