If you find vac leaks or FP faults, just clear the code and run it ..if it was cured , the code will not come back up b/c you have solved the problem and the system has re-adapted within the limits.

However, as JF has stated , they found that as the engine wears , the adaptations limits of the original were found to be too close a limit for normal adaptations and by upping the +/_ percentage of his modofication, it gives the systsem more limitation % lee-way.
I have even seen a dirty a/filter bring on a code 19 with the OEM system..
But is your engine management system is in real "On The Money" running conndition, [ meaning no leak, wear, fuel mix, etc], then it will run within OEM limits just fine. There are many out there that do not bring on a code 19 and they have the OEM set-up.
A trick to do after you find any leaks or FP problems , is to get that code 19 cleared and then after you get a single Flash [ designating No Codes Stored], you then wait 2 secs, press button 6 sec , turn off key for 2 secs , on for 10 secs and start car...this will clear the adaptation memory back to mean [ zero] so the ECU does not have to readapt with drive cycles..you will then know you are starting with a zero base-line and if it hits adaptation limits after that memory clearing, then it has come from zero, not from the OLD adaptation memory that was set before the remedy...
Less chance of getting a false code while the system re-adapts that way..

__________________
A Dalton