Need help with engine noise

[TXAtty]

Have been experiencing a valve clatter type of noise during light acceleration (1200-1500 rpm). Took it to the dealer for help - 1st time was told could not find anything wrong via the Tech II - and was told to bring it back after they had a chance to discuss it with GM - brought it back for a second time - of course they came back with "we tested it as per GM instructions (turning off cylinders one at a time to isolate the noise) and the noise is normal". My truck is an 02 with 35,000 miles on it. I have driven other DMaxes with the Allison and the noise is not there....Noise started about 10,000 miles ago - It is not the "tick" (I have it) or the pilot injection turning on and off.

Two questions:
Has anyone else exerience this noise?
Should I be concerned with the noise?

[dmaxalliTech]

Injector knock can be mistaken for internal engine noises. best thing to do is drive truck with T-2 and monitor balancing rates, balance rates with be 0 under accel but at idle, it may show something, you are looking for 4 to -4 degrees, anything out of that range is injector issue likely. have tech go for a ride with you duplicating noise and have him watch flow rates, may have one way of compared to rest... just some thoughts