Lincoln Repair Questions? Ask a Mechanic for Answers ASAP
Hello and thank you for your question,The code Po174 is a lean code and the common cause for it to set is usually a leaking PCV supply line. Start with checking the supply line from the engine to where it connects to the PCV valve located in the passenger side valve cover. There are known issues with the hose rotting out at the intake where it connects.As for the heater, if you warm the engine up and go out under the hood and place your hand on both hoses to the hearer core at the firewall are they both getting nice and hot?
If you have had time to check the hoses and found them both to be hot then you are likely dealing with a bad blend door actuator. Post back if that is the case and I will post the steps to replace it. Let me know and we can work from there.