I have a 1999 Suburban 5.7L...I used three different diagnositc machines. One said map sensor or the FAV sensor, misfiring, another one said the timing was 16 degrees off but it's non timable motor or an automatic timing motor. The third one at a garage said it was a P0135, the cam and crank sensor. I'm going to start out with the plugs and wires. Any suggestions would be greatly appreciated.

 

That's a good solution