05 GT stalls while driving...HELP!!?!
 

So here is my problem:
I have an 05 GT V8. I have the issue with "DTE FLI DATA ERR" code that shows up. We've had it in the dealership and replaced fuel sending units more than a couple times (Sorry, it's the fiance's car, I'm going off her word for pre-me time).

But lately, I've been having an issue with it stalling on the freeway. In Houston, that means trouble. When we first leave the house, the idle drops down to about 400 RPMs, and the motor tries to die. Hitting the throttle, I notice there is a delay in the response. I have figured out that when it acts this way, if I pop it in N, shut it down and restart, I don't have the problem as often.

But she tells me it happens when she is on the freeway, usually in either really hot or rainy weather, and/or stop and go gridlock.

I noticed last night the check engine light is on, she says it sometimes goes off. I keep telling her to go get the code read, but she doesn't. I'm going to have to take care of that. But hopefully someone else has an idea of what is wrong. It seems like something in the idle to me. Any one else have any issues like this?

I would think they checked at the dealership but a couple things I'd suggest, if you haven't done them already, replace the fuel filter and clean the throttle body.

my first suggestion would be to completely remove the throttle body and clean it with throttle body cleaner. A can of cleaner only costs a couple bucks. Mine was doing the same thing, CEL and it would not idle. After cleaning the throttle body, it was perfect.

There are 2 bolts and 2 nuts that hold the Throttle body on and a couple of electrical connectors to the sensors. Take it off, use the spray and paper towels, put it back on and life is good.

Mustangs get oil blow-by into the intake and it gums up the Throttle body, This is why oil catch cans are popular mod that will keep the throttle body cleaner.

I have read that the water leak TSB onto the SMB can cause this issue, on top of the fuel pump issue TSB. I agree with the above posters on cleaning the TB also, my 06 idle was crazy until I cleaned all the sludge off the TB unit.

Replace the fuel filter and clean the throttle body. I can almost guarantee this is the issue.. It's also super easy to do both of these things

mine had the same problem, i clean the throttle body and worked fine for about 3 months just stopped when i replaced the TB control.

As stated, most likely the TB but also change the fuel filter for good measure. The chronic water leak onto the SJB (one of many TSB's) and/or the fuel pump issue (another one of those TSB's) wouldn't cause the described issues.

Probably be a good idea to see why the check engine light keeps coming on, then you can proceed with proper diagnosis of the concern.

Toothbrush and cleaner and a rag to clean the throttle body back and front.

Be careful of the sensor in there though.

But I feel this isn't a problem. I've experience rough idle because of this, but never this.

You mention that this happens when it is hot or raining? Is the A/C on during those times? My car has the same symptoms when the A/C is on. I have found that the problem is more prevalent with the C&L racer intake and SCT tune installed as compared to stock.