Last week, I had the battery replaced on my '05 GT. Soon afterward, it began idling funny, with the RPMs bouncing between normal (I wanna say 700RPMs, is that right?) and maybe 300. It's even worse when the AC is on, and the RPMs will sometimes even dip so low as to stall the engine. Soon after the trouble with the idle began, the Check Engine light came on.

I took it to the Ford dealership abd explained to the service manager what happened. He said to take it home and simply disconnect the battery and leave it disconnected for 5 minutes. After I did this, the problem seemed to be completely rectified, but a short while later it returned.

Anyone have any ideas as to what might be causing this and how I might fix it? I've got 49,000 miles on it, so I'm waaaay out of warranty . . .

TIA for any advice and input!

[IMG]local://upfiles/74200/BA2BD9B8212B4BE09A47B446D9E6CEC2.jpg[/IMG]

 

Might be thefuel pump or the fuel pressure regulartor.

Oh, and welcome to the forums!

 

If anyone was doing something under the hood, a vacuum line may have been knocked loose. That would cause funny idle and check engine light. I would think that it would do it all of the time though and not run fine occasionally, like after you unhooked the battery for a bit. But, it might not hurt to check or listen for a hissing while running.

 

The guy at the dealer told me that sometimes when the battery is changed and all electrical power is cut to the car, that the "idle control" in the computer is thrown out of whack, and that disconnecting the battery "reflashes" the computer. I think it almost has to be something electrical, as the problem coincides with the changing of the battery.

 

Yeah, that might be a good idea, I'll look/listen for that in the morning . . .

 

If you had a CEL there their should have been some codes... if it happens again stop some where like Autozone or one of those places that will read the codes for free..

My car was doing that, but was also turning on the wrench light... it was either the throttle body or the throttle positoin sensor... and since the throttle body came with a new throttle position sensor... well, i just got a new TB and problem went away...

 

Defineately take it to AZ or somewhere to get the codes checked. Best of luck to you, post the codes when you get them..