I have an 98 tahoe with a 5.7 i was wondering how to set the timing. i have read on here to use a scan tool. so i got a bluepoint YA3140 scan tool. heres so of the live readiings map 9.1 ,eng rpm 650, spark adv 22, maf .808 . no matter where i move the dist. the spark adv. stays between 22 - 24. i have read it should be 0 +/- 2. it runs ok but starts hard some times. any help would be greatly appreciated.

 

Spark advance is not the correct item. You need to look for "cam retard" . Also after each turn of the dis you must snap the throttle above 2000 rpm to update the reading.