A compression check and cylinder leak-down test should tell you the condition of your engine.
Type your answer here... Hello how do you reset the check engine light on a 2003 Toyota 4runner. Thanks
http://www.extreme-check-engine-light-codes.com/Toyota%20OBD1%20Decoder.htm
Low fluid levels in engine.
there could literally be thousands of causes...most auto repair places will read the code and tell you what is wrong for free...
you would have code "pending" and a check engine light
Sorry need a few more details. What model 4 runner do you have and what year? What is the engine size?
remove the efi fuse for 1 minute if the light comes back on you have a problem
open fuse box remove efi [fuel injector fuse for about10 seconds
It could be anything, but the most common problem is the O2 sensor.
how do you check the oil for the front transfer case on a 1990 Toyota four runner
Could be one of a thousand things. Go to a shop and have them read the error code.