I have a 2006 GT, 4.6L v-8. From time to time I am experiencing "Surging". At one particula instance, the car defaulted to the "Limp Home" mode,(poor acceleration, no shifting into overdrive, throttle control indicator light on. After being shut off for an hour, the car ran perfect with no problems. The computer failed to indicate any history of the problem, however the surging has begun again. Is this a problem with the throttle body or could it be a sensor going bad?

 

I would check and clean the TB. I would change the fuel filter. Both are very easy to do. If you unfamiliar with it....... I followed the DIY directions from American Muscles instructions link. Thats where I bought the fuel filter.
I would do those first and see what happens. Are you sure your fuel is good? No water in there?

 

Last thread I read about this was the fuel filter. Good luck though.

 

Have your alternator checked. My wife's car was having the same problem, turned out the alternator was only making 43 amps.

 

Try to grab a code if your engine light comes on. Which I think usually does happen when you get limp mode.

Fuel filter and throttle body cleaning are great places to start.

Is your car tuned and do you have any mods?

 

Water is not going to cause it to go into Limp Mode. I can explain all the things that can make this engine to go on Limp Home mode but I'm not.
Fuel filter will cause if he hasn't done it ever 30k miles
He would also notice hard to start.
How many miles? Any other mods?
Sounds like a TB sensor and MAF. I would clean the MAF and replace TB sensor if your TB has signs of sludge

 

I was going to get at this.

OP, did this limp home mode occur within a few days of a good rain or pressurized car wash?

The reason I ask for codes (aside from them being very useful) is because I had an issue with a sticking throttlebody though it was clean and then replaced. I got limp home mode and the codes indicated the throttle position sensor was incorrect. Testing with a multimeter and replacing the TB and the TBS proved that those were not the issue. (See my other thread: https://mustangforums.com/forum/4-6l...r-issue-2.html which I will be updating after I fix one more issue when it's warmer). I had the dreaded water leak and I began noticing every time it went in to limp mode was after a heavy rain or going to a self serve car wash. I had water pouring in to my car right on top of the Smart Junction Box. After stopping the leaks and drying everything out, I haven't had limp mode since then.

 

My 06 did the surge thing a few times at very low speeds. I have since changed the fuel filter and cleaned the TB. No surging since I did these fixes, Knock on wood!

 

True water on the SJB will corrode the terminals no doubt,which will throw off your reading causing it to go to Limp mode, but he hasn't mention any codes so that leads me to believe that his TB sensor is going bad if he has build up on the TB. Also, he didn't state his miles so... I usually go by miles since I know what to expect.

 

My racing cams causes my stang to surge :P lol