Hey guys i just bought a 06 5.9 trx4 the other day and it seems like a great truck and only has 112k miles on it. I think i got a pretty good deal. couldnt find rust anywhere except the exhaust mani but thats normal. it does have a chip on it, a powerplay mp8? But i just noticed when i was revving the engine up it revs down kinda slow and somewhat rough like its trying to stay revved up. I'm not sure how to look this up or what its even called, but does anyone know what could be causing this? I'm assuming the chip but I dont just want to unplug it and mess something up.

 

Its normal rail drain takes a few seconds!