OBD code po108. RPMs erratic and engine surging at idle

wow , you actually tried to look it up, a 1st time here.

the MAP is a baro sensor used to calculate fuel injection RATES.

if you have gross air leaks to the system the engine IDLE screams.

is it?

108 means the voltage is too high.

usually its unplugged, or bad sensor.

otential causes of a P0108 code: Bad MAP sensor Leak in vacuum supply line to MAP sensor Engine vacuum leak Short on signal wire to PCM Short on reference voltage wire from PCM Open in ground circuit to MAP Worn engine causing low vacuum



Bad MAP sensor Leak in vacuum supply line to MAP sensor Engine vacuum leak Short on signal wire to PCM Short on reference voltage wire from PCM Open in ground circuit to MAP Worn engine causing low vacuum



http://www.obd-codes.com/p0108



and last. but before ECU.

low engine compression, is 1 more, causes , many



what i do is reseat the MAP sensor

i then make sure he vacuum port is not clogged. (both sides)

i then measure the output , keyon, and idle and gunning throttle.

any Voltmeter works here,

key on is 5v or near.

idle 1.8v

gun engine as the RPMs fall like a rock the volts tries to hit 0.5vdc.



http://www.fixkick.com/look/odds-ends/jeep/MAP-sensor-output-real.jpg



very very easy to find with a voltmeter

if the meter agrees with vacuum gage, then the MAP is ok

and you have air leaks or low vacuum for (VAST reasons)

ask.

Code 37 is torque converter clutch solenoid failure. Transmission wont shift in and out of overdrive.

Hi there,

Erratic idle is often due to a vacuum or air leak in one of the engine systems, or faulty sensors sending incorrect data to your engine's computer.

As your vehicle is OBD-II compliant (ie has OnBoard Diagnostics) your engine computer will have stored the appropriate fault codes.

Before you start changing any components, always have the codes extracted from your onboard computer as this process will quickly identify which circuit (or sensor) is causing this condition. Changing your TPS may have been unneccessary.


Cheers,




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Here are the most common causes of idle surge, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

98 ford explorer erratic idle from cold reves jump. ok when warm but still stalls at times.

If the engine seems to run fine over 1450 RPM maybe there is a vacuum hose leaking or EGR valve is slightly stuck open. Any help from the OBD II trouble codes? Or is there simply no MIL and no stored information in the OBD II computer read at the local parts store through the connector by the drivers knee?

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

the idle speed is controlled through the on board fuel injection control module (known as the PCM), even if u raise the idle at the throttle body the computer will slow it back down, however there is a problem that causes slow idle, do the following procedure to correct the slow idle issue, follow it exactly.

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Your ignition core could be going bad. One simple and free! thing you could try is to goto Autozone or Advanced Auto store (if you live close to either one) and ask if you can get a OBD scanner/diagnostic tool hooked up to your car. They don't charge anything for this service. Hopefully, some code or codes will show up on the diagnostics, and reveal the possible problem.

Good luck!

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Here is the most common cause of surges and stalls at stops and low erratic idle speed and rough idle, it is the idle speed control air-bypass valve and throttle valve (IAC for short), they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake