ok guys i need your help here i just installed a new weiand manifold on my 98 z28 the car runs great with the exception of eratic idle but its throwing codes p0507 and p0108 i know one is idle over stock settings and the other is the map sensor i think but what would have caused this maybe the increased plenum size i'm at a loss so i you could just shoot some info my way i'd be gratgul

 

ok i figureded out that p0507 was caused by the cruise control cable and the other hasn't poped back on so i'm guessing its ok now i hope?

 

P0507
The PCM controls engine idle speed by adjusting the position of the Idle Air Control (IAC) motor pintle. The IAC is a bi-directional motor driven by two coils. The PCM sends pulses (steps) to the IAC to extend or retract the IAC pintle into a passage in the throttle body to decrease or increase air flow. The commanded IAC position (displayed in counts) can be monitored on the scan tool; a higher number of counts indicates more commanded airflow (pintle retracted) This method allows highly accurate control of idle speed and quick response to changes in engine load. If the PCM detects a condition where too low of an idle speed is present and the PCM is unable to adjust idle speed by increasing the IAC counts, DTC P0507 will set indicating a problem with the idle control system.

The PCM will turn the MIL OFF during the third consecutive trip in which the diagnostic has been run and passed.
The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
The DTC can be cleared by using the scan tool Clear Information function or by disconnecting the PCM battery feed.



P0108
The Manifold Absolute Pressure (MAP) sensor is mounted to the rear of the intake manifold. The MAP sensor measures the pressure changes within the intake manifold which is an indication of the engine load. The MAP sensor has a 5.0 volt reference, a ground, and a signal circuit.

The MAP sensor contains a diaphragm which changes the resistance based on pressure. When the manifold pressure is low (high vacuum) the sensor output voltage is low. When the manifold pressure is high (low vacuum) the sensor output voltage is high.

The MAP sensor voltage (depending on altitude) can range from 1.0-1.5 volts at idle (high vacuum) to 4.0 - 4.9 volts at wide open throttle (low vacuum).

When the PCM senses a signal voltage higher than the normal operating range of the sensor, DTC P0108 sets.

The PCM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A last test failed, or current DTC, clears when the diagnostic runs and does not fail.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.

 

i thank you for listed all that but i found the problem it was the cruise control cable getting hung up. but thanks again

 

No problem.. Glad you fixed it!