Engine Overheating

In the past week I've noticed my 2003 Chevy Venture running hot occasionally. For the most part it runs pretty well, but then it will begin to idle very high, and the tempeture will spike if I'm not in gear. Also, when I'm in drive it seems to accelerate on it's own, even going uphill. Any ideas?

Define spike, idle very fast, and how hot is it getting?

When I put it in park the engines sounds as feels as though I was holding down the gas pedal. As for the temp, I don't know the exact temp, but the temp guage goes over 3/4. Closer to the 'red' zone then I care to be.

It had similar issues 4 months back and at that time we had the intake manifold replaced.

The symptoms don't seem the same this time (besides the overheating). Also, the 'Check Engine' and other sensor/warning lights are all remaining off.

From other posts I've seen here people have had lots of problems with the Intake Manifold and overheating, but it doesn't appear to be a reoccuring problem like I'm seeing now.

Are the fans kicking on? Normal temp for my van while moving is 195 (the same as the thermostat). If I let it idle for a long time it will go up close to the red before the fans will kick on. It looks like it's too high, but it's normal. This is on a '98 Montana. The later models have a different temp gauge so I can't say exactly how yours should compare.

How's your coolant level? Check both the reservoir as well as the filler neck (when engine is cold). The radiator should have close to the top of the neck and the reservoir should have enough antifreeze so that the end of the hose is submerged. Otherwise it will suck in air as the system cools.