4.6 RPM drop when coming to a stop sign

[eddie95]

Well, its doing it again. Taking it to the shop on Monday

 

[Number4]

Have you been disconnecting the battery through all of this? More importantly, did this all start happening after having disconnected the battery?
There is a TSB out for these engines depending on whether the car is over or under 10k miles. In other words, some vehicles had this problem quick and it was covered.
The throttle body gets coated in crap (oil) coming from the PCV (?.)
When you disconnect the battery, the computer forgets it's learned settings. Has to re learn them. Every time I have to disconnect the battery, the car runs like crap for about a month. Only at stop signs though and usually after it's warmed up a bit.
I did wipe clean the throttle body blend door and surrounding area, this helped a lot.
Not sure if it's your problem, but everyone here is talking about the same fixes that never work if you read other posts. Basically, the blend door is not adjusting properly at low RPM until the computer learns to overcome the crud.
Some people install the air/oil separators in the pcv line to fix such issues.
I've installed a new pcv and have the gaskets so I can yank the throttle body and thoroughly clean it. There's actually a special coating on these TB units that's supposed to prevent this issue. Doesn't work to well and points to the fact that Ford new about the issue from the design stages. hmmmm...

 

[eddie95]

I have been disconnecting the battery, but I've always done the reprogram procedure that was outlined in the manual and it ran fine for over a week after the last time I disconnected it before I had problems. Also, as you probably noticed by the date on the posts, it used to do it to me once or twice every couple weeks, and a couple months later now its doing it all the time. So, I appreciate the advice, but I'm going to take it to the shop and let them figure this one out. I'll be sure to post what they found on here so that people can refer to it.

Have you been disconnecting the battery through all of this? More importantly, did this all start happening after having disconnected the battery?
There is a TSB out for these engines depending on whether the car is over or under 10k miles. In other words, some vehicles had this problem quick and it was covered.
The throttle body gets coated in crap (oil) coming from the PCV (?.)
When you disconnect the battery, the computer forgets it's learned settings. Has to re learn them. Every time I have to disconnect the battery, the car runs like crap for about a month. Only at stop signs though and usually after it's warmed up a bit.
I did wipe clean the throttle body blend door and surrounding area, this helped a lot.
Not sure if it's your problem, but everyone here is talking about the same fixes that never work if you read other posts. Basically, the blend door is not adjusting properly at low RPM until the computer learns to overcome the crud.
Some people install the air/oil separators in the pcv line to fix such issues.
I've installed a new pcv and have the gaskets so I can yank the throttle body and thoroughly clean it. There's actually a special coating on these TB units that's supposed to prevent this issue. Doesn't work to well and points to the fact that Ford new about the issue from the design stages. hmmmm...

 

[EndFed]

Throttle Position Sensor, my guess. imp

Hmm. That wouldn't throw a code though?

 

[imp]

Hmm. That wouldn't throw a code though?

It should. However, that code would have to be electrical, rather than mechanical. I'm thinking of the throttle plate position vs. the position sensor being out of "kilter" somehow. Just a thought. imp

 

[eddie95]

Well, I couldn't get an appointment until today. I'll post an update tonight. It has been stalling every stop until last night and this morning. Hasn't stalled in the past 24 hours lol. I think I have a gremlin

 

[eddie95]

Well, they can't find anything wrong with it. No vacuum leaks, no stored codes, nothing. The only thing they did was clean out the throttle body. It ran great again all day so I'm at my wits end.

 

[andykwells]

Did you ever figure this out? I'm having the same problem.

 

[lincolnshibuya]

This is a classic IAC issue. A cleanup or a new Motorcraft IAC will help. The aftermarket IAC are a hit and miss thing, you could get lucky. Buy it online it's 50% cheaper than the dealership.

 

[XploX]

Yep...IAC.
Do get a Motorcraft. There is a difference, don't ask how I know.