[Phoenix_23]

Hi I was here last time asking bout the air control valve cuz my rpms kept stayin at 1 1/2 they told me to buy a new one I did but its still doing the same thing xan some one tell me y its still doing the same thing I got a new one from autozone

[Green_6er]

what was on while it was doing this?

[Phoenix_23]

Nothing it was in neutral going 25 mph

[00MustangGtPremium]

How often does it do this and when?
Also it could be the idle screw. Inplug the IAC and see where the rpms are at. Then adjust if needed.

[Phoenix_23]

It does it all the time only when im driving & whats the idle screw wheres that at? Also whats iac mean ?

[00MustangGtPremium]

Originally Posted by Phoenix_23 It does it all the time only when im driving & whats the idle screw wheres that at? Also whats iac mean ?

The idle screw is the screw on the throttle body at stops it from closing all the way. What you need to do is unplug the connector at the iac and see what the rpms are. From there either turn the screw on the throttle body clockwise or counterclockwise to open (allow more air, raise rpms) or close (allow less air, lower rpms). The screw might be allowing the iac to open too much.
IAC is idle air control or idle air bypass.

[Phoenix_23]

Like how while the cars on or what ?

[00MustangGtPremium]

yes while the car is idling

[Phoenix_23]

Ok but what if at iddle it runs normal it does it only while the car is running not on iddle

[00MustangGtPremium]

Originally Posted by Phoenix_23 Ok but what if at iddle it runs normal it does it only while the car is running not on iddle

When does it do it?

[Phoenix_23]

While its in motion when its at iddle its normal today my rpms kept going up & down in neutral while in motion

[00MustangGtPremium]

Originally Posted by Phoenix_23 While its in motion when its at iddle its normal today my rpms kept going up & down in neutral while in motion

It sounds like a bad tps (Throttle position sensor). Its the black thing on the side of the throttle body. I found an article that will help you see the voltage at the tps and adjust it if needed

How To Adjust TPS
"Muscle Mustangs & Fast Fords"
April 1993
The throttle position sensor is one of those things that falls into the category of "computer stuff" that makes a big difference and is easy to deal with, but average people like us would never know about. Without the proper adjustment, the throttle position sensor (TPS) will give the computer a false reading as to the exact throttle opening. A false reading will limit wide open throttle performance (something we definitely don't want). A voltage reading must be taken using a digital volt/ohmmeter (DVOM) with the Key On/Engine Off and with the Key On/Engine Running. A Radio Shack DVOM, part No. 22-185A, works well for this job.
The TPS is located directly on top of the throttle body and is adjusted by loosening the two phillips mounting screws and swiveling the sensor until the highest reading is found. It may be necessary to elongate the holes with a small file to achieve the desired reading.

The spec range for Key On is from .88 to 1.0 volt; shoot for the .97 to .99 volt. With the engine running, the voltage should be no higher than 1.05 volts.

Incorrect Throttle Position Sensor (TPS) voltage will result in reduced performance. The best way to take a TPS voltage reading is by using two safety pins through the wires coming from the sensor. The positive lead is attached to the green wire, while the negative goes to the black wire. Always ground the meter through the sensor's black wire. This gives a direct, and more accurate ground into the computer.

[Phoenix_23]

Dam sound confusing...

[00MustangGtPremium]

Originally Posted by Phoenix_23 Dam sound confusing...

lol it could be for a beginner. As long as you read the directions thoroughly and know what everything is, it should be a piece of cake. You could also get a forum member in your area to help you

[Phoenix_23]

Do u know of any who know bout ths stiff that stays in phoenix,az

[00MustangGtPremium]

I personally dont but either a mustang garage or a forum member in the area would be glad to help you out

[Phoenix_23]

Whta a mustang garage ?

[00MustangGtPremium]

Originally Posted by Phoenix_23 Whta a mustang garage ?

I mean a garage that specializes in mustangs. Im sure theres a few in Phoenix

[Phoenix_23]

Oh ok thanks

[00MustangGtPremium]

sure thing bro. Thats why were here