I just bought a 2005 ford f250. it's got an aftermarket exhaust, K&N cold air intake and piping and it seems to be laggy. on the open road it runs great and the factory gauge shows a peak of about 18psi. it's an auto tho and off the line it takes a solid 5 seconds to build any boost or move out of its own way. I had 2 cummins rams before and they were drag racers off the line. this one has 98k miles and with the after market piping and such i was wondering if i might have a boost leak, or if this is normal for these trucks? are they normally pretty laggy? mine really boosts around 3k with some coming on around 2.5 - which seems high to me.

also, I've heard these models have notorious head gasket issues. anyone know what the symptoms are to look for?
with a gas engine I could do a compression test, but not sure with a diesel.

thanks for any info guys !