my truck won't talk to me

[Hunter95R]

I have a '94 Supercab with a 4.0. I can't get it to do a KOER test to save my life. it will do a KOEO but, not the running test. I've tried three different types of scan tools and nothing. Any ideas?

 

[RustedRanger]

If you think something is wrong or it's acting up have it put on a diagnostic computer,it can find out much more than a scan tool. Doing that saved me money by finding the real problem instead of replacing unneeded parts.