I'm having a problem right now with two symptoms that started at the same time. When the engine is cold, it will start but only stay running if I keep my foot on the gas and keep the RPMs above 1k. Once the coolant temperature gauge rises to the second marking, and only when it reaches that same point each time, it will run on its own.
On its own, you'd think it would be the coolant temperature sensor or something like that. But the other problem that began at the same time as this one is a loss of high RPM power. Under normal circumstances, the engine pulls decently to 3500 RPM and then really surges in power above that, but since my problem began, there has been no higher rpm surge, and above 5000 RPM it simply runs out of power. It's to the point where it will rev higher, but as soon as you go into the next gear and the revs drop back down, there's actually a surge of power as if there's more horsepower lower down in the revs than in the upper power band.
So to sum up, these two problems began at the same time. The symptoms are that the engine will not idle on its own until warmed up and runs out of power between about 4 and 7k RPM (though this seems to vary slightly depending on the day, but it is never "normal").
I've also ordered a new high pressure hydraulic hose which will hopefully cure or at least help pinpoint my hydraulic issues. I currently have a lack of steering assist and the brake pedal is stiff on the first stop or two and loosens up suddenly.