:dunno:I Have a 1998.5 cummins 24v with the current modifications 4'' Down pipe,Six inch straight pipe, K&N Filter, Superchip Max Micro Tuner. A few weeks ago I installed the superchips tuner and had an amazing difference in power The truck Ran 15.193 And now a few weeks have gone by and the truck felt like it was running alot slower. Ran it again now its back to the 16's Can anyone help me. I cant seem to figure out what the problem is the truck runs completely normal just gradually getting slower.
