Here is a link to my OBDII live diagnostics while driving the vehicle. Still trying to figure out why the check engine light is tripping with a P0171. This is my son's vehicle, but I am the one he comes to to get things fixed. We (meaning he holds the flashlight) have done brakes, a wheel bearing and tie rods so far. Now he tells me his check engine light has been on and sometimes when going slow into a parking lot his truck will just turn off. We sprayed carb cleaner around every area to check for vacuum leaks (twice) and we have taken the throttle body off and cleaned it. It does not have a Mass Air Flow sensor. Here is the live data . Any help would be greatly appreciated.

 

4.2l is noted for intake manifold bolts loosing up. Check ALL bolts for proper torque - 89 in lbs.

 

Thanks for the info.

 

The check engine light comes on and then goes after after a while and then comes back on. My son says he can "feel" when the check engine light comes on because his truck becomes very sluggish.