Got a stock 99 Blazer with a 4.3 that has broken 2 sets of starter bolts. using a regular scanner it shows 44degrees of initial timing. i pulled the tune for it and compared the timing tables to a stock one off the repository. it was all the same. it had a bad cam position sensor. i watched the timing going down the road with the old and the new sensor. old sensor would swing 15 to 20 degrees under no load on flat ground. new one maybe 3 to 5.
