Well been off here for awhile but just bought another Diesel its a 97 4x4 5spd anyway heres my problem I got it home and I noticed a thumping noise coming from the air box, when i cover the turbo tube alittle it seems to go away I think its a bent pushrod or my valve lash can anyone tell me exactly how to check the pushrods???

 

could be a valve or adjustment, or rocker, or push rod, or cam lobe. Remove the valve coversand check the adjustment, while the rocker is in position to adjust, just spin the pushrod to see if it wobbles or turns true. Check the height of the valves, should be the same, if one is high the valves are pounding into the seats. For the cam lobes, start the eng up with the covers off and watch the rockers for equal movement. It's not scientific but the way you described the thump in the intake you are looking for something obvious and if the cam were bad enough to cause a thump in the int, the lack of rocker movement on one cyl will be obvious. Also the lash adjustment will be real loose on one cyl. Good luck