Anyone ever adjust 02 Mack engine valves? Or is it advised to adjust ever so often? I have noticed a slight tick on first start in the morning it goes away after a couple minutes, sounds top end like maybe a loose valve. Also how about injectors is there any maintainence. My #4 injector light comes on and off. If i had a bad injector would i notice a bad miss? or would it be suttle.

On a 2002 Mack you might be best to get a dealer to adjust them this time around.  There are several updates to the rocker shaft bolts, and they should be changed every time you adjust the valves anyhow cause they stretch and come loose.   When they break you're usually into a cam.   If you regularly adjust the valves (every 3000 -4000 engine hours or so) you'll save a pile of $$ in the long run. 

as for the injector code, the eup (the fuel pump for that cylinder) should be swapped out for a new or reman one.  You can easily do this yourself.   Snap a pic of the tag on the eup before putting it in - the next time you've got the truck Computer plugged in or at the dealer you can enter the trim code for that eup into the ecm to keep the engine running nice and balanced (You might not notice a difference though).  While you're torquing in the new eup, check the bolts on all of the others - they have a habit of breaking allowing the eup to pop out of the block spilling diesel into the crankcase and on the road abe being stuck with a tow or service call.   

Thanks Green Guy, yeah i would have a mechanic i know or dealer adjust them. It could be something else like air compressor or an exhaust leak also but good to have a close ear to your investment. It actually runs great except for this small Tick. I'll have to look into the injector and pump like you say. I've never investigated into the system (which i will in time) I didn't know each cylinder had a pump. Once i knew a guy that had a injector fail and it was a spring in the injector lever, that went. It left him with a smokey no power machine he nursed back to the shop.

thx greenguy