I have begun to notice that when I start my van each morning for the first time that it is reving at a higher RPM then it did back during the winter. During the winter it may have been around 1000rpms at start before lowering down after a few minutes. Now it is starting at about 1500 and then returning down to the lower level after a few minutes of warming up. Could the change in outside temps cause this?
Yes but I would be thinking that over the winter a rubber line may have been stressed beyond its elasticity point…being so cold out. The most common hose suseptible to flexing and cold temps is the hose running from the airbox to the engine…the MAF sensor is installed in this hose. WHen you step on the gas many x that hose has to flex in order to keep up with the engine moving in its mounts…it may have developed a crack and thus raised your rpms… The other suspect is your AIC valve…could be gummed up and need to be cleaned…this valve relys on a proper level of engine coolant also…so check that…the AIC cannot function properly with low coolant…Low coolant would give you higher rpms when cold bec the AIC valve doesnt know how hot or cold the coolant level is…bec the temp sensor is not properly submerged in coolant.
So…look for vacume leaks… Then check your coolant level then look into the AIC valve operation… All of these can contribute to your higher than norm rpms at startup. Hope this helps…
I can rule out coolant, that area is fine as I check it weekly and it’s always kept full, will look into the hose issue.
It could be the temps.
If it lowers to the proper RPM I would not give it a 2nd thought. Drive on.