Originally Posted by exbrick
The lag is just the transient while the ECU adjusts for the sudden change in throttle position. It shouldn't be that noticeable but it takes the fuel system a few moments to catch up. Think about what's going on inside the engine. At the instant that you nail that the throttle there is a very sudden flood of air into the engine. This results in a lean mixture until the air mass meter and O2 sensor tell the ECU what's happening, at which point the ECU adds fuel. Lean = less fuel = less power. Some ECUs actually revert to open-loop at WOT which brings the mixture all the way over to rich. Rich = air is displaced by extra fuel that won't burn = less power, too. That's to protect the engine from pinging and unsightly CELs. So I really doubt that there is anything wrong with your car at all. You can check for vacuum leaks as others said but otherwise just go a little easier on the throttle.
Very well put, and correct.
Calculate the time from the point when you floor the accelerator to the point of the car actually accelerating. Also take into consideration it's an automatic, and there will be a delay because the transmission has to downshift to the correct gear to match the power that resulted from the air/fuel mixture.
This delay can be capitalized buy letting the car breathe a little better. Intake, Header, & exhaust would help. Or, you can get a throttle spacer to better the response of the throttle. These steps would help in the response, but will not eliminate the delay.
The best way (my opinion) to get a better response is to get a manual transmission. The only delay is the time it takes you to downshift