I noticed over the month or so that I have had my 1994 4 runner with the 3.0, that when I start it cold, it likes to hover around 1600-1800 RPM'S. Whens its warm it likes 900-1100. I replaced the valve cover gaskets, cam plugs and plenuim gasket last Saturday, and I noticed that when I put everything together, both perameters were raised about 200-300. So I lowered it to about 1100 for warm up, and about 500 for idle. Is this too low? Also I was curious if the higher RPM ranges it was at was contributing to my horrible gas mileage. I about using about half a tank to go 80 miles.