I do think it is caused by dirty oil. Remember it is the oil that controls the fuel injectors. I try to change my oil about 6K miles. As I believe the cleaner the oil the better it is.
Last year, I worked with a fellow 3126E owner, finally he located a very smart Cat computer tech (young). They tried to isolate the issue, finally he ask, what he did within the last month before the problem. His reply was I changed the oil. As he had nothing to loose, he did it again. I have not heard of him having this problem since then.
I would rather change my oil twice a year, instead of having a HEUI failure.
