I have an 87 4wd AT. This is my second van - the other was an 86 2wd AT. I noticed that this one has considerably less power than the other. I di realize that this is a smaller engine but I am wondering if I have another issue.

I recently aquired it and after a tuneu took it on a long drive. After about 600 miles I started losing torque and hearing a loud clicking sound. After checkig I saw that it had almost ran out of oil in dip stick. This means it used maybe 1-2 quarts during that 600 miles! The van doesnt leak oil nor is there any smoke coming out. One of the things I noticed was that the lack of oil was directly related to an almost complete lack of torque - I could only go 25 on the hwy.

Any idea what the issue might be as far as oil being used up and could that issue result in a low overall torque even when oil is topped up?