[gtnateam23]

Ok well when i start my car and let it idle it surgess up and down then stalls out and when i am driving it it runs great but sometimes it seems like it cutting in and out unless i just give it more gas.....Unless i unplug my mass air then the car will idle but ofcoarse its not goin to run right. And if it is plugged up it surgess and stalls out but i can also pull the front vacuum hose off the bottum of the upper intake and the car runs and idles fine but again not the right way to fix the problem.....I have talked to a mechanic and he said i need to clean my mass sensor...done still does it so i dont know what to do now im kinda thinking the mass sensor is goin out but not real sure thanks for the help.

[nolife]

Search google or this forum for mustang idle surge or mustang idle hunting, you will find MANY tips and detailed checklists of what to check to help you narrow down the problem.

One example is here

[1slo5.0]

Originally Posted by gtnateam23 Ok well when i start my car and let it idle it surgess up and down then stalls out and when i am driving it it runs great but sometimes it seems like it cutting in and out unless i just give it more gas.....Unless i unplug my mass air then the car will idle but ofcoarse its not goin to run right. And if it is plugged up it surgess and stalls out but i can also pull the front vacuum hose off the bottum of the upper intake and the car runs and idles fine but again not the right way to fix the problem.....I have talked to a mechanic and he said i need to clean my mass sensor...done still does it so i dont know what to do now im kinda thinking the mass sensor is goin out but not real sure thanks for the help.

Tap on the mass air meter when the car is idling (with the mass air sensor plugged in obviously...). Does the idle change at all? The reason why it runs better with the vacuum hose off is because you have created a vacuum leak which causes a lean condition and increase engine rpm. Here are some other things to try:

10 Pin Connector modification:
1. Take the 10 pin connectors apart (salt and pepper shakers).

2. use a pick like tool to spread the male terminals open more so they make better contact. In the center of each male terminal there is a small seam and seams down the sides of the terminal which allows you to spread them open.

3. Apply some dielectric grease to the terminals

4. Plug the connectors back in.



Throttle Position Sensor (TPS) adjustment:
Without the proper adjustment, the throttle position sensor (TPS) will give the computer false reading as to the exact throttle opening. A false reading will limit wide open throttle performance. 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.

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 drill bit or small file to achieve the desired reading. The spec range for Key On is from .88 to 1.0 volt; shoot for the .90 to .98 volt. Make sure voltage reaches/exceeds 2.71v at WOT.

Incorrect Throttle Position Sensor (TPS) voltage will result in reduced performance including a possible hanging/surging idle. 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.



Resetting the base idle:
1.Clear the computer's idle memory by disconnecting the battery for 20+ minutes.
2. Disconnect the Idle Air Bypass solenoid
3. Reconnect battery
4. Start engine and set idle speed to desired RPM with idle screw on throttle body
5. Turn off engine and reconnect the air bypass solenoid
6. Set TPS voltage between 0.90 - 0.95 volts with a digital volt meter
7. Start engine and let it idle for 2 minutes with no accessories on.
8. Turn off engine for two minutes
9. Start engine again and run for 2 minutes with every accessory turned on.
10. Turn engine off again.

[gtnateam23]

like everytime i rev the motor up it will idle fine for like 5 to 10 min then starts the idle surge and stalling all over again

[jack90gt]

Mine did the same thing then i adjusted the fuel pressure and that cured it....

[gtnateam23]

may i ask what you adjusted your fuel pressure to because i have tryied it ans it didnt seem to make a diff