96 Ram 2500 360. While trying to diagnose a slight power problem and loss of mpg I did a vacuum check as described in the Haynes manual. While idling hot I read 17 in. hg. When I snaop the throttle toaround 2500 and let off quick it drops to almost 0 and then spikes around 24 and then levels down to around 18. however while doing these test over about 5 minutes I noticed me idle reading was creeping up to over 20 in.hg. If I hold the RPM around 2000 the vacuum increases to about 22 and holds until I let off. When I let off it spikes up to about 26 and then back down to idle reading. Is this normal? I am losing a bit of oil so I checked the plugs and they are actually pretty good. 1 had a little bit of deposit on it but overall good. I looked in the throttle body to see if there was oil in the plennum and there appears to be a tiny hint of oil. Also the butterflies have a bit of oil on the outside edge. Any help would be great.

 

Vacuum readings look good and normal. Given the year of the truck, I wouldn't be too concerned about a "bit" of oil loss.
WC
Oh well, it worked once, what the hell. Check your pcv valve and hoses.

 

But my oil loss is about 3 quarts in 600 miles. Only 100 of that was working the truck. No smoke and no drips.

 

OK. 3 qts in 600 miles is a BIG "bit" of oil!