I have a 98 1500 4x4 w/360. I changed the oil in september to synthetic. the truck has 136k miles on it...but my check gauges light started coming on around turns and when i checked the oil 2 weeks ago..i only had one quart of oil! somehow it went through 4 quarts in 3.5 months! I started looking for leaks and it isn't leaking anything sitting or running. i was going to check the intake gasket like people are always talking about but was told that there really isn't any oil that goes through there that would be leaking, just antifreeze (i have plenty of that, it's not leaking). needless to say, i didn't touch anything. it isn't smoking like cars usually do when they are burning oil. it just has a little cloud when it first starts and that is it. when u rev it up, it has a really almost condensation cloud that smells like carbon not smoke so i'm 99% sure it's carbon. I have no clue what to do. another thing that is bothering me is that it seems to have a whole lot less power than it should with the programmer and all of the other parts that i put on it. another thing that it is doing is it has a really rough idle when it sits cold. if you let it kind of struggle through it it eventually evens out and runs smoothly and won't idle rough again that day. I was trying to get some ideas of what might be wrong. If i have to replace the engine then i would like to drop a 5.9L cummins in it instead of putting another 360 in. my truck is an automatic. What would i have to do to drop a cummins engine in cause a buddy told me that the mounts and stuff are in the same spot and the engine bay is the same size as the 2500 and 3500... I was just curious. Any help is awesome!!!