Not with a 2.9, but my 99 4.0 did that... twice.
First time was cracked heads, second time was a leaking head gasket. Diagnosing the problem the first time like to drove me up a wall. Had a bad missfire, took it to dealer (too many times) to find out what was wrong with it. They kept telling me I had a bad spark plug, I think I replaced the plugs three times and wires twice in one year trying to fix the problem. Turns out all they were doing was pulling the codes and checking the plugs, never dawned on them to see why the same plug kept going bad. Of course it took a bit before I realized that's all they were doing, but once I did it was time to pick up a compression tester. Sure enough one cylinder was way low. Pulled heads hoping to get away with a gasket change but had them checked, turned out both were cracked. Replaced with new stronger castings.
About a year or year and a half later the problem returned but not as bad. Once again no signs of leakage in the oil or valve covers, but I did notice that I was slowly loosing coolant and assumed there was a small external leak somewhere. Turns out this time a head gasket went but it was my fault. Was using one of dad's torque wrenches, one that was his dad's and probably hadn't been calibrated since his dad passed over 26 years ago. It worked fine for most things it was used for but apparently head gaskets are too sensitive to torque values. Bough a new torque wrench (needed my own anyway) replaced the head gaskets, and haven't had a bit of trouble since. (Don't worry I knocked on wood.)
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It wasn't until the head gasket blew out the side of the block that I could finally find a leak.
