Hi. I have a 2005 Mustang GT that has been experiencing a lag between pressing the accelerator and the vehicle accelerating. It happens most frequently when the car is still moving but you've let off the gas to slow down (but not stop) and then try to take off again when traffic begins moving. It's done this for years but seems to be getting worse. The delay is so annoying and causes a jerky acceleration when the gas pedal and engine (?) finally talk to each other. Anyone else experienced this? What was the issue/fix? Thanks!!!

 

There are two reasons why your car may do this. One is the DBW set up takes pedal position and translates it into throttle blade angle. This can be adjusted in the tune. The second is about the pedal assembly basically being a mechanical device that requires contact between the little metal brushes and some strips of metal.
sometime due to factory tolerances there can be an actual dead spot near the beginning of it's movement where proper contact is not established. This can be corrected by opening it up and bending the little wire brushes or to shim the gas pedal arm so it makes proper contact from the beginning.



This only addresses the initial lag that you have been experiencing. It getting worst is another issue. When was the last time the TB was cleaned? When was the last time the car was given a tune up? Do you have a factory PCV system? Do you still have charge motion plates between the manifold and heads? Have you re-calibrated the pedal lately?

 

It's hard to tell just from your description, but could TSB 06-9-9 be what you're experiencing?

https://lmr.com/products/2005-Mustang-TSB-Recall

 

Thanks, I do think that is one issue that I missed years ago when the TSB was issued. My dad thinks there's something wrong with the accelerator itself and possibly more at this point.it idles very rough with perfectly timed surges. Guess I'll have to take it to a shop to see if they can pinpoint the issues! Appreciate the message!

 

Try cleaning your throttle body. I had this issue years ago and thought it was the accelerator as well. Search the forums for how to clean the TB and it makes a big difference.

 

What 05RedGt said. Try that first.

 

Could be also your fuel pick up on your pump is dirty not allowing fuel to pass , I get crap in my fuel always , so I bought 100 pick ups. Or you could have a coil pack short , like water in one of the spark plug sockets , always blow out the dirt then remove coil packs to inspect , I've had water get in & cause a misfire. When you do this get some die electric grease to add to bottom of coil packs/plug& injected conecters

 

Here's a few more on a fuel pump pick up & when it can't suck everything you described happens, the white bag is a 100 fuel pump socks slightly smaller but are for these 05-09 pumps because Ford will not sell them they want you to buy an $750.00 pump. The top picture the round white part is the bottom of the sock directly obove it has goes into the pump, now when the mesh is all clogged up it try's to suck up the white flat part thus closing off fuel supply