Tex sounds like something is up and it sounds like it is something with you!!!
Go buy a brand new home breathalyzer, do not open it and go straight to a doctors office. Explain to them exactly what happened and request a blood draw to check your BAC, then have the doctor open the breathalayzer and see what you blow.
The reason I am saying this is because obviously there is something about you that is causing false positives on breathalyzers and having a doctor certify that your blood BAC is 0.0 while you blow a positive breathalyzer will be admissable in court and may actually result in the whole thing being thrown out of court if you go to the prosecutor with the results from your doctor.
Please keep us informed on what you do.
Tex do some reading here
Breathalyzer - Wikipedia, the free encyclopedia there are a lot of things that can cause a false positive, bring this up both to your doctor and to the prosecutor.