i have a 03 explorer sport trac. im geting code p0507 . so someone told me it the Mass air flow sensor. so i went to the auto store and pick up mass air flow cleaner so the light went out for 3 day .now it back on again no air leck that i can see . not saying there is none .now someone telling me it a egr . i dont have the money to spen. Mass air flow sensor cost $9.00 and the egr im looking at is $31.99 . i was just hoping that someone can tell me what to look for so i can get this ligh out .

 

Most OBDII codes are universal, and this one is actually for a higher than expected idle speed. Basically, the engine at idle is turning faster than the computer is telling it to. This can be from a vacuum leak or a malfunctioning throttle.
Are there any other codes?

 

just p0507. and there was one more after i clean the Mass air flow sensor that one went away .
it said some thing like (too lean)
if the idle is setup to hight on the tack side. where is it to be on the tack. right now it on the 1 just idleing

 

If it never drops below 1000 rpms on the tachometer (or 1 x1000), even after a short drive, that is too high. Do you know if your 2003 has an electronic throttle body? Is there any roughness to the idle, or does it idle very smoothly?

If the throttle is not electronic, but cable actuated, you might hold the throttle open with the engine off and clean the throttle body and back side of the throttle plate with throttle body cleaner to see if a build up of carbon might be preventing the throttle from closing completely. Be aware that depending on how much cleaner you spray, it could make starting the truck the first time after the cleaning quite difficult and it will likely idle very roughly for several seconds with a lot of exhaust smoke until it burns away all the dirty cleaner.

-Rod

 

it is smoothly went idleing .
(clean the throttle body and back side of the throttle plate.) i did that with mass air flow cleaner .
( it could make starting the truck the first time after the cleaning quite difficult ).i found out already lol .
garage had just it the idle went the light was on about 6 mouth ago but the light went out for about 1 hour then came back on . it may need to be trun back . what i need is what the rpm is to be at so i can set it back . im thicking about 700 to 800 rpm.
im getting about 9 mile par gal . i thick my truck like being drunk of off gas too.

 

You used the MAF sensor cleaner to clean the throttle plate? I suppose that might work, but I'm not sure how effective it would be. Throttle body cleaner seems quite a bit more aggressive than MAF sensor cleaner. Did you also clean the MAF sensor?

The idle should not need to be "turned back", it is completely controlled by the PCM. If the idle is not right, there is an issue somewhere.

Since you also have poor fuel economy you should carefully clean the MAF sensor is you have not done that already, then consider changing the Engine Coolant Temperature (ECT) sensor. If the PCM thinks the coolant is colder than it really is, it will set a high idle and enrichen the air/fuel mixture. Also, Ford uses an ECT sender for the temperature gauge in the instrument panel so the temperature the gauge shows the coolant temperature being could be completely different than what the PCM thinks the coolant temperature is. If you have access to a scan tool with datastream mode you could monitor the ECT to see if it makes sense. After sitting overnight, the ECT should be pretty much the same same as the ambient temperature.

-Rod

 

If the idle was manually adjusted, that may be giving you an issue now. The old OBD I trucks were much more sensitive to the initial throttle plate setting, if it was messed with at all the engine would surge and stall every time it came down to idle.
There is a setting for the throttle plate clearance, it is around .006-.008" clearance with the throttle against the stop for the earlier ones, I do not know what the spec is on this one though. It may be in the FSM.
That setting would be a good place to start, after that start hunting for vacuum leaks. I have seen the PCV vacuum line disintegrate on Fords of this year range.

 

The specified idle speed at idle is shown on the label clearly visible when you open the hood.

 

Actually, here is what they say:

Ford has said the same thing on every EFI vehicle they have made.
The code indicated is for higher than expected idle speed, IE more air is coming in than the computer thinks should to the point it can't control it with the idle air controller.
The idle absolutely should not be manually adjusted, the throttle blade position must be set properly to factory specs or things like this happen. When I was in automotive school I spent two days trying to figure out a 91 with a random stall at idle, including six hours with a break-out box pinning out every single input and output for the computer with a scope to check the signal, only to stumble upon the incorrectly set throttle on accident. Since then, after obvious vacuum leaks that has been my first check for an idle problem, and has saved me countless hours of diag time. The usual process is that a customer has an idle problem, adjusts the idle, since that didn't fix it they change the IAC that should have been changed or cleaned in the first place, but the problem is still there. They then bring the car in, and usually spend a few hundred on diag fees to find something that isn't even on the diagnostic tree. It's not an issue limited to Fords, either, I have used this technique on a few different makes with the same result.