Lance Armstrong on another Federal Investigation

Lance Armstrong is reportedly the target of a RENEWED federal criminal investigation connected to his rampant drug use during his cycling career ... and could face serious time in the slammer if convicted. 

Just weeks after Armstrong fessed up to cheating his ass off on his way to 7 Tour de France titles, ABC News is reporting that feds are actively investigating Armstrong for obstruction, intimidation, and witness tampering.

If Lance is ultimately prosecuted -- and convicted -- a judge could sentence him to federal prison. 

Multiple riders -- and other people close to Lance -- have publicly accused Armstrong of threatening them into silence over the years ... but nobody really listened until Lance went to Oprah and copped to being a jerk. 

According to the report, investigators are not concerned with Armstrong's drug use so much as they are with Armstrong allegedly threatening and interfering with witnesses who could have testified against him. 

It ain't the first time Lance has been investigated by the feds -- Lance was under the microscope from 2010 to 2012 following allegations of drug distribution, fraud and conspiracy -- but the investigation was dropped. 

This time, Lance might not get off so easy ...