Code P1506

Check the PCV valve, and its hose.

I realize this will sound goofy but I cant find it. The 'book' says it is located on the rear valve cover towards the right side.I do not see it.

The PCV valve is below the induction air tube and throttle body assembly area. There is an oil separator on the bottom of the intake that is connected to the PCV valve through a hose.

Replace the valve and tube, should take care of problem, let me know

There is two lines coming from the valve covers but do not have PCV's in them. I did see something attached to the firewall and going the the bottom of the throttle body intake hose.

Feel below your throttle body, there is a tube under it, follow that tube it will lead to your pcv valve, Its a tuff one, you can barely see it.

I think we are both on to something. I will not know until tomorrow when I get a new one and figure it out. I will keep you posted. Thank you

Make sure to tell the parts store or where ever your getting one its for the DOHC, Ive had trouble getting the right ones. Actually think I've gotten them from Ford.

Ok, so I replaced the DPFe and it didnt do the trick, shocking. I broke down and got the PCV valve. The damn thing was in the middle of the valley under everything! Good times my friend. I started it up and it did not rev up high as before. I am hopeful this will kill the dreaded light and pass inspection after I get it through the drive cycle. I will repost the whole situation once inspected so anyone else having this problem can help someone else.
QUESTION: it might have been a mistake but I didnt replace the hose. Can that be the source of a serious vacuum leak?

As long as the hose looked in good shape, you'll be in good shape, the pcv should be the problem and I think that this will take care of the problem. I have dealt with this problem personally on a couple of tauruses, they are a real joy to change, Im glad you got it done and let me on the outcome. It might take a certain number of key cycles to clear, if you dont want to wait, maybe if you have or can get access to a scanner you could clear the codes.

Well, that is why you are the expert. Thank you, it finally passed inspection. Here was the total scenerio for those battling this beast in the future. 2000 ford taurus DOHC came to me running rough with engine light on. The codes were P-1151 lack of HO2S21 switches-sensor indicate lean, 301 misfire cyl #1, 302 cyl #2, 303 cyl #3, 171 fuel system lean, 174 fuel system lean, 1506 Idle air control over speed error. I first started with new plugs, platnuim paying attention to the temp range that is required and the gap. I sprayed the engine while it was running to listen for changes in the idle and determined the upper intake gasket was leaking. I changed both because if one is bad, the other probably is and they came as a set. Haynes manual gives a high torque spec to the intake to head bolts so torque to 89 INCH LBS. Replaced a set of bolts. This improved the performance greatly but didnt kill the 1506 code. I sprayed again for intake leaks and was confident that there was no more vacuum leaks. I replaced the IAC (twice, cause I thought the first one was bad. It didnt change the engine speed when I unplugged it but later found out that it wasnt bad.) I did more research and arrived at the DPFe sensor (EGR system sensor)and replaced it. It helped the high idle again but no good for the code. In between each of these 'fixes' I conducted the drive cycles and cleared all monitor except one or two and then 1506 would pop up. Spent a few bucks in gas for that. So, I got on here and PROTECH1980 gave me the advice to change out the PCV. It IS located in the center of the valley under everything. I had to remove the intake and fuel rail to get to it as it was under the wiring harness. Thank you for all your help.
P.S. How are you with a '97 T&C with a p0700?