What I am saying is you can check hoses and stuff for vac leaks, but if a purge or egr valve leak, the leak is internal, so you do not see it..but the engine sure does,
So, they are hard to find and require a hand vac pump and gauge to really check. many times you can narrow it down by cappin each one and trying the car ..if the problem goes away, you may have found the culprit.
The real way is to get adaptation values and try and correct from there.
And again, with the small % window , the car may require that much adaptation and be normal. Even a bad/weak 02 sensor or clogged air filter can cause/require higher than normal adaptations in order to correct for the condition.
If you had the values and they were close, you probably need the extra % the mod would give you, but if the values are way high, the higher % mod is not going to solve the problem, but may just mask it.
A Fat guy can't climb thru a small window, but he can go thru a larger one...However, he is still too Fat .......
..and a normal guy can go thru the small window...
Not much of an anology, but you can see what I mean.
Does your car pop a code b/c of a fault , or is running and trimmed in as close to normal as possible, but just has too small an operating window %.
As said, the original was a borderline, small window that did not allow for a system that needed just a little more adaptation..that is where the mod comes in..[ and why Benz enlarged the window on later models] ..but don't think the mod changes the adaptations the car is requiring to run corrected..it does not..it simply does not trigger a CE at the higher adaptation % b/c the window is now larger and that means the CE does not pop b/c the adaptations are no longer higher than the new , larger window..ie, you got a bigger window now that allows for higher adaptation w/o CE warning...