2004 ISX or not?

The first gen ISX engines were a bit problematic, and they took some time to work them out... not sure if they had it mostly worked out by 2004 or not, but I'd want to see a complete service history if I were in your shoes.

 

Drove a 2000 500 ISX for about a year. I think it had about 300,000 on it when I got it. It was a company truck, and passed down to me.

The only thing I remember being done to the engine before and while I had it, it was in to set the overhead, and then I went to the dealer once I believe to have the speed reset. (75mph.) The gentalman hooking the computer up, commented that if it was my truck and not a company truck, he could dial in some big power. No amount of bribing would change his mind. lol It only had a 16 pound Super 10 (my favorite transmission, by the way) and he could not turn up the torque.

It did not have the beef that the 475E Cat that I had come out of had, but once up and rolling, pulled pretty good.

Loved that CAT..... Both were in the same model truck and geared identically; both got almost the same fuel mileage.

Company ran mostly the 475E Cats, and they were almost bullit proof, also. The one I came out of, I think had about 600,000 on it, and at 10,000 miles, which is where they changed it the oil, it was full, and still looked like new on the dip stick.

Sorry, got tangential. I did really like the ISX engine as well....

 

I own a T600 with a 550 ISX and am not a huge fan. First thing to do would be to unplug the EGR, lots of posts on here telling you how. I am trying to get rid of mine and go back to a cat.