bluep7

I am planning on cleaning out my T/B and IAC with CRC throttle body air intake cleaner.
Is it possible to clean the ERG valve also and if so, what do you clean it with and what are the benefits if any? Or is it just worth it to replace it with a new one and what are benefits of that? Can it save me repairs down the road? Do they have a history of going bad?



Thank you

BTW 2004 GT

cliffyk

FWIW--from the 2004 shop manual, which BTW makes no mention of any necessary periodic maintenance for the TB, or IAC or EGR valves:



If you do clean it be gentle, just spray don't scrub off the coating--you may need to readjust the throttle stop screw if you get too carried away. FWIW I have never cleaned the TB on any car with less than 200k miles on it.

Re: the IAC, also from the shop manual:



There is a rubber diaphragm in the IAC that can be damaged by the organic solvents in some cleaning solutions, also a lot of what keeps the IAC from "honking" (see this thread), and actually minimises metal-to-metal contact is the accumulated carbon.

The TB and IAC are both fine examples of the "If it ain't broke..." school of thought.

You can try to clean the EGR, but most of what is in there will be at the inlet and caked solid, you may find the tube clogged up too...

bluep7

Holy S***. I am so glad your alive. So basically what your telling me is just leave it alone?

Thank you!!!

bluep7

Cliff, I read this thread https://mustangforums.com/forum/4-6l...e-the-iac.html you had posted and have another ? for you. When do you know you need to replace the IAC? When I am stopped ad at idle I feel it is idling funny, but I really can't be sure. How can I be sure and should I just go ahead and replace it to dispel my worry? I have 64k miles on my 2004 GT. Thanks again. Your a wealth of knowledge.

cliffyk

Describe "idling funny"? It is normal for the '03 and '04s to have a bit of a "lumpy" idle--if the idling funny is not the idle speed moving up and down by 50-100 rpm or more then it is not an IAC issue, it is just natural for this engine.

You can test the IAC as follows:

• With the engine warm and idling disconnect the IAC electrical connector, the engine rpm should drop significantly or even stall--if it doesn't the IAC is bad buy a new one;
  
  
• You can check the IAC with a multi-meter, unplug the electrical connector and measure the resistance between the two terminals, it should be 6Ω to 13Ω--if it isn't the IAC is bad, buy a new one;
  
  
• Next check the resistance between each terminal and the IAC body, in both cases it should be better than 10kΩ--if it is less thee IAC is bad, buy a new one;
  
• Check the voltage between the red wire at the IAC (connector plugged in, key on engine off (KOEO) and ground (the IAC body will work), it should be 12.0V or more--if not you have a wiring problem.

At 64k miles it should be OK, most start to "honk" or fail the above tests when it's time to replace it.

You may want to pull the COPs and inspect the boots for a "burned smell" and/or signs of arcing or hardening; and while they are off maybe replace the spark plugs, even though Ford says they are good for 100k miles. I use Champion stk # 3401 single platinums, they are around $3 at most FLAPS...