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792 views 1 reply 2 participants last post by  codewize 
#1 ·
Hey guys, I have a 93' sts 4.9L. and my problem is that when I start to drive as I accelerate and then let go of the gas my speed pretty much sticks the same like if I was always in cruise control, as I decelerate to come to a stop it seems like my rpm's go up and when im at a complete stop it will go down to normal, but my idle does go slightly up and down and doesnt stay consistent, I havent changed anything under the hood except plugs. If you guys have any info on this sort of problem it is greatly appreciated.

Thanks
STS love hate relationship!!!!!
 
#2 ·
I know I'm going to compare apples to oranges BUT this sounds exactly like what I just fixed on my 4.5 STS

see the post in this thread called 4.5L Idle Problem Solved!! Thanks, *********

Now the 4.9 doesn't have an ISC but rather an IAC (Idle Air Control) that in combination with the TPS (Throttle Position Sensor) is what controls the problem your experiencing.

I would say that one or both may be out of adjustment OR bad.
 
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