need help my car is sick

[White94GT]

For the past few days, my car has been idling bad. my car usually idles around 500 rpm's, but when i''m at a stoplight it will go up to about a grand, then fall down below 500 then shoot back up then go back down, and sometimes the car dies when the rpm's go down. does anyone have any ideas what it might be. i need new spark plugs and wires and i'm getting them soon, could that be the problem?

 

[Quick5pnt0]

If you haven't done so already the first place to start is by cleaning the IAC, TB, and MAF.
Take a look at the link below and at the end of every page there is a link to the next article in the series that will show you how to do all of what i said above.
I hope it helps!
http://www.muscularmustangs.com/iac.html

 

[94TURBO5 O]

Mike good info dude once again.
Use this info as a reference point to start with as these are the common problems with our cars. If you have not changed plugs and wires thats good to do that but that won't make you surge like that if they are bad.

 

[stng94]

TPS. This caused a surging idle on my car, not to say it is your problem, but it is easy to check with a voltmeter.