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The TB and intake flats are NOT dead flat, there are tiny stands holding them slightly apart, meaning you have a small gap in between them that can then allow the very thin portion of the TB gasket at the IAC bypass port to flip over sideways to leak then it seals back up when engine cuts off. It can happen again and again and in a week or a month, whatever God chooses to do. I for one took my TB and ground the high little stands down dead flat on a piece of glass to then seal tighter at that gasket after having trouble with it and not a peep further out of it.

Do NOT reuse a TB gasket, you will be tempted to as they come off looking fine and they will even rebound a bit to get thicker looking like new. The DENSITY of the silicone has changed from heat exposure though, the old one will be floppy loose but the new one will still be much stiffer to seal better. The new silicone is much denser.

The IAC CAN send a code, for hitting limits,, it will say 'not able to control idle' or something close. That is the IAC code. What will likely show up if one adjusts the screw in it to pull the calibration off center. One side then ends up short and the other long and the short side then hits limit.
 

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Discussion Starter · #42 ·
UH, the butterfly does NOT fully close and never should. The IAC range is set up for a certain amount of air to go through the butterfly aircrack that is at idle. Why the setscrew to set that 'leak'.

I clean pretty much most of my butterfly without ever removing the TB, simply open the throttle and clean the edges of it. I have never cleaned the inside of an intake and no need.

Lumpy idle and high idle rpm are two sides of the same coin. Likely vacuum leak. You can have that leak and fuel pressure one from injector too, no law says otherwise. If you hold pedal down to stop flooding the other three injectors will be off too and engine may well not start at all.

And yes, I likely have the only two Focus cars in the US with schrader valves on the intakes.
What I was trying to imply as when you do a pedal to the floor flood clear then let the pedal up then try to start it it should clear the flood if it was flooded.
Otherwise it could be the IAC not opening at all to let air in on a cold start. Don't agree with the vacuum leak it's done this like once every 6 months where the idle goes up to 1200 and stays there that sounds just like the IAC and it is for a very short time. And it's right at the 1200 RPM of the IAC high idle point.
 

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Discussion Starter · #44 · (Edited)
We'll wait for you to fix it............luck.
OK here is the deal , it sat almost 3 full days , I logged live data for the 62 frames it allows~3 minutes starting logging with engine off. ABSOLUTELY NORMAL. Not buying vacuum leak or leaking injectors. Only does it every several months.
TBH points to IAC sticking closed on cold start robbing it of needed air making it too rich , then on SAME drive cycle RPM was stuck up at the 12-1300 which would happen if the IAC was staying open too long. When it happened , I shut it off , it reset and NEVER happened again.
Can I post the live data on here some how or PM it to someone ? Fuel trims normal , RPM drops from the IAC commanded 1200 promptly as it warms up drops to 750. Air cond. on idle bumps to proper 800 and is perfectly smooth. I will just order the same IAC Ford brand from rockauto that I HAD in my hand 9 months ago. The price for the IAC and double O-ring seal was $60 total , now it is like $86 !!! insert face-palm:rolleyes:
Also can someone who is not guessing , but knows for a fact what it takes to set an actual IAC code ? Mine has NO CODES.
I have read it has to be way out of range , like broken to set a code.
 

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Discussion Starter · #46 ·
A good guess is better than a bad proof.

o_O
I suppose I could go to a Ford dealer and get the right answer , esp. if I pay. In 2002 OBD2 was not as sophisticated as now. My former dealer mechanic friend could see it on his high-dollar scanner but it would have to be acting up at that very moment. I bet the IAC duty-cycle could be logged.
A new IAC is less than 1 hour of dealer labor. 😂
 

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Not a question of good. You want people to study your data for free. Maybe someone else. Not me.

A diagnosis with absolute certainty is not always possible. At some point you buy parts and take your chances.
 
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