96 gmc Yukon 5.7 whippled extra injectors ,flowmaster basically stock.

I have the elm 5 scanner and my timing is always in the negative. I hava a i did a couple of runs wot and idle in gear in 3rd -21 to -23 punch it and maxs out at -15 all the way through to red line. It doesnt ping or knock very little at redline if it does .

Is this normal for a forced inducted engine or is time for a tune ?

Thanks all for any input.


The ces is not on . THanks to a new mallory distr. gear . WOW