my car's heat guage is inflactuate up and down, It goes up with starting with increasing speed some time its come down and some time it goes up, I do'nt understand whats wrong with this guage?
spelling issues aside, it sounds like you are low on coolant or you possibly have a faulty thermostat. Some of the Ventures also had an extra electrical water pump that could cause this problem. You probably should take it too a shop.
Check your oil level with your dipstick.
If it's a chocolate milky color : instead of the normal brown/black.... you probably have a bad intake manifold gasket.
The GM 3400 engine has a reputation for this problem.
If that's OK then check your coolant levels, you just may have to add some coolant.