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Richard, ASE Certified Technician
Category: Ford
Satisfied Customers: 15544
Experience:  12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.
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2002 lincoln ls: blow revs up an down...when..petal

Customer Question

heater does not blow warm air.what can i check to find out what is wrong. 2002 lincoln also car revs up an down all the time.when i try to take off i have to put petal t floor before it will go
Submitted: 6 years ago.
Category: Ford
Expert:  Richard replied 6 years ago.

Hello and welcome to


First make sure the engine is warming up to temperature. If it is then the usual cause is a faulty Dual Coolant Control Valve. This valve is located on the bottom of the fan assembly on the passenger side. They will get stuck closed causing lack of flow to the heater core. See if both the top inner hose and bottom hose are hot on the firewall where they enter the core. Those are the driver and passenger inlet. The top outer is the return as that should be hot too. If the outlet is cold then you have a clogged core. If the inlets are cold then I suspect a faulty coolant valve. For the idle this is usually caused by a sticking idle air control valve located in front of the throttle adapter assembly. You can try tapping on the valve to see if the problem lessens.