Rough Start - Sometimes

hello every one.....i have a 96 3.0 v6....started up my car today and it started up faster then normal so i was really please lol...but then the rpms would drop and rise at idle....from 500 to 1000...just drop and rise at idle...i was scared it might just turn off...so i waited until it stabelized it self..this is the third time in 4 months...im thinking maybe its the fuel pump going bad?...maybe?...idk any suggestions?.........thank you.

hello every one.....i have a 96 3.0 v6....started up my car today and it started up faster then normal so i was really please lol...but then the rpms would drop and rise at idle....from 500 to 1000...just drop and rise at idle...i was scared it might just turn off...so i waited until it stabelized it self..this is the third time in 4 months...im thinking maybe its the fuel pump going bad?...maybe?...idk any suggestions?.........thank you.


Which engine is it the vulcan or duratec??

Have yu cleaned the throotle body and IAC?

i cleaned the IAC but it still dint look clean enough to me..so just spent the 60 bucks and bought new one...put it on and bam..problem solved...like a brand new car...problem is it has too much power....i was going 30 down the street and not even touching the peddle( a little exageratuion :) ) 30 minutes into the test drive i get a check engine code...checked it and it was p1506....i checked what that code meant and it is the Idle Air Contol Overspeed ...and it makes sense cuz it has a lot of power = overspeed....now i checked the possibilities and they dont make sense..they range from leaks to other valves and stuff...i dont get it because everything was FINE, no check engine before i put the new iac on...so i know it doesnt need other parts / valves and if it was leaking how can the hoses wear out to start a leak in 15 minutes?....could it be they i didnt tighten the iac down enough?.....

what could it be?

Did you replace the IAC gasket when you installed the new IAC? Have you checked to make sure it's seated properly and you didn't cross-thread a mounting bolt? Have you cleaned the throttle body yet? If the throttle plate is not closing fully for some reason (carbon build up, throttle cable interference from working in that area, etc.) it could cause the overspeed. Be sure to thoroughly inspect for vacuum leaks. The car is getting old enough that you won't have to get very rough with some of the rubber and plastic parts to cause them to crack.

-Rod

ok well i didnt get time to keep checking it, so i was going to wait for next saturday to keep at it in the morning..mean while i was just going to drive it like that with the overspeed feel and check engine light on....while going to the grocery store the check engine just turned off...and the overspeed idle feel...just...stopped...now my idle speeds are at a constant 1000 - 1,200 rpm..always....theres no rise and low at idle...and the check engine overspeed code just turned off....it feels faster like it reaches 2k rpm easily , and it still feels like it has a lot of power but not like before when i wasent even pushing the gas...thank you so much shorod and tempfixit....thank you guys alot...

Shorod was right...the IAC gasket was kinda loose...so i tighten up the whole thing and everything felt much better and more normal..thank you shorod....just that that i should update you.