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Idle lag/stumble

3553 Views 7 Replies 4 Participants Last post by  XR650R
So I had an interesting event yesterday. After work I went to get a carwash, it's too cold here to wash by hand still, and right before the dryers kicked in my car started to lose idle RMPs. I normally idle around that 1000-900 area but the car dropped to 500 and came back up, back down and back up and down once more to where I thought it would stall out. I had it in neutral and was just sitting there at the time. When the door went up I didn't even dry the car, I just went to the parking lot and sat. I did manage to catch it doing it again. Went from 900 to 500 back up then down to 700 and came back. I decided I needed to get it home and it hasn't happened again.

Anyone else have anything similar happen? The closest thing I could find was after filling up with gas but I didn't fill up yesterday. This morning on cold start it ran fine but I did notice when I got to work it seemed to idle low and was around that 700-800 range.
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Mine does this on a cold start. When I start the car and turn on A/C (something you have to do right away when it's 105 F outside and 120 F inside), after I start driving, first stop I come to rpm dips to like 300, car shutters, ECU kicks them back to like 1100, they go down to like 900 and stay there. Only happens during my first stop. Yours might be having some wiring issue. Try to catch it on a video, then go to the dealer and show them everything.
Yep, video evidence is your best argument. If dealer doesn't buy it, a call to Ford corporate with the issue + saying you have video evidence might quickly tip the scales in your favor
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