When I first crank my jeep engine speed jumps to 2000 rpm then slowly goes down to 1000. It does not matter if engine is warm or cold. Also my temp. control on my heater will not turn the heat all the way off. I have warm air blowing when set on vent and temp control turned all the way down. Could I be having a vacuum problem?
Normal for an engine to start at elevated rpm and then die back as it takes a few seconds for the ECM doing it's sensor checks and idle back to the correct idle speed
check the idle rpm with an external rpm counter as most in dash units are inaccurate at rpm lower than 1000
as for the temperature
If you have a climate control module, it uses a mixture of heater and ac to maintain the temperature that you have set
so check it for operation
SOURCE: VACUUM HOSE DIAGRAM FOR 1988 JEEP WRANGLER 4.2 I6?
here is a link with all the vacum diagrams for your jeep. hope it helps.
http://www.autozone.com/addVehicleId,1076002/initialAction,repairGuide/shopping/repairGuide.htm?pageId=0900c1528008ab9d
SOURCE: engine over heating 2002 jeep 4.0 liter
Check water pump and make sure that its working. Should be circulating antifreeze in radiator and in engine. You can also check and the head gasket and make sure its NOT blown. Good luck and thanks for using FIX YA
SOURCE: Jeep AC blows cold air at defrost and feet but not through vents
There is a flap that directs the air. the flap is controlled by a vacuum actuator. This is located inside the venting. The actuator is connected to little vacuum hoses that attach to the temperature control switch. Either the flap is stuck, or the actuator has gone bad.
SOURCE: 1997 jeep wrangler ac will not blow out of main
Maybe your dashboard vents are clogged, obstructed or stuck in close position somehow.
If not, check the air hoses that carry the cooled air to the main vents are not clogged, bent, ripped or simply detached.
If its practical for you, check if they are correctly placed, clean and general conditions are ok if you can.
If above are not the issue, go to check outlets of the A/C unit, its filters for the possible reason.
SOURCE: Describe your 1997 Jeep Wrangler 1997 jeep
The check gauges light is normal because at 400 rpm it isn't running fast enough to build sufficient oil pressure. I am guessing maybe a vaccum leak???
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No. This is not normal. This started a couple days ago. It is about twice the RPM's of what it normally is.
this is normal idle speed control.
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