I have a 2004 Taurus with 58,000 Miles.
it has the 3.0 Vulcan engine.
When I am sitting still and I slightly let off the brake to roll forward " but still holding the brake" I feel the engine surging forward at a fast pulse a small pulse every half second or so. Also after the car has warmed up it seems as if it lacks power, but when the car is cold it has no problem getting up to speed, The car does good at highway speeds but accelerating up to them is a hassle.
Also there is a poping noise coming from the airbox, I've taken it to a ford dealership before and they fixed the problem but it is back now, when they fixed it they took off the air intake manifold and said something was loose causing vibration.
For some reason he also removed the valve covers because I had to return the car because he did not replace the gasket correctly and leaked oil on my exhaust manifold. From what i've read the surging is probably caused by MAF or 02 Sensors, the computer has no codes. I did have the car taken in when it was under warranty for the idle being rought " jumping around 750/1000 Rpms" they replaced the IAC now the rpms are jumping around agian also when the car is sitting there you can distincly hear it rev up and down in a 1 second pattern, thanks for any help