I have a 1993 ford ranger, 2WD, shortbed, stick shift. the engine is a 4 cylinder. I have a problem with it. it wont start but it cranks. the battery is fully charged when starting it also.so we checked for spark. no spark on any of the 8 spark plugs and the spark plugs are brand new with nothing wrong.we tried to look for a bad connection but couldnt find one. Any ideas what could be the issue?