Need help engine pulse

[Grabberblue]

So Ive had my 2003 sport trac for about 5 months now. It recently started pulsating upon starup. Its very hard to explain the problem. It doesnt happen in the mornings, normally when i get off of work. Ill turn the key and go to drive and it will start pulsating, its enough that it makes me move in the seat. The quick fix i have found for it is to put it in park for a few seconds and then its gone.

If i can give more information let me know what you need and ill go check. I really appreciate the help everyone!

 

[swshawaii]

Pulsating? Never heard that one. Maybe surging, vibration, or missing. Does it occur right after starting? No check engine light or trouble codes? IAC, MAF, and throttle body cleaning should be considered preventative maintenance. The PCV elbow is also a common failure that doesn't always throw a CEL or trouble codes. More details and description please.

 

[Grabberblue]

It could be described as surging too. Its just right after start up. once it passes it doesnt happen until the next statup, but it doesnt happen everytime. there is no check engine light on either.

 

[swshawaii]

Idle Air Control (Do this first and see if it solves the surging issue)
http://www.mysporttrac.com/mysporttrac/projects/CleaningIAC/CLEANING_IAC_MOTOR.htm

Throttle Body
http://www.mysporttrac.com/MySportTrac/projects/ThrottleBodyCleaning/Throttle_Cleaning.htm

Rather than removing the MAF sensor from the housing, just spray the wire filament thoroughly with
CRC MAF Sensor Cleaner or Electrical Contact Cleaner and let it dry. (Do NOT touch the MAF filament)
http://www.explorerforum.com/forums/showthread.php?t=350613

 

[gamikzone]

i had a problem in my ranger that i had before the ST, sometimes when i would start up the engine would turn on but then the truck would start shaking and the lights flicker it looks like it was about to turn of until i gave it some gas, it was occasional though.