SOURCE: 2006 pt cruiser idles high with no pcv valve hose connected
Replace the PVC valve, it's probably clogged.
SOURCE: my xj6 runs at high rpms and accelerates on its own
None of those possible problems have anything to do with idle speed. The first thing might be a very weak throttle return spring. The next would be a sticky throttle cable or foot feed pedal that isn't moving freely. Another possibility is a vacuum leak somewhere. Did changing the spark plug in #1 cylinder help the misfire? If not, you may have a partially plugged injector. Fixing the misfire will only increase idle speed some more. Look for an idle speed motor near the throttle body that is supposed to raise idle speed when the engine is cold and lower it back when the engine warms up. Check to see if it is holding the speed too high. If the throttle position sensor tells the computer where the idle speed motor is set, then it could have an effect on idle speed if the sensor is bad. The position sensor is just a fancy potentiometer. Hope some of this helps.
Testimonial: "thank you!"
SOURCE: 2000 buick lesabre transmission - high rpm's in 1st to 2nd gear
SHift solenoid pressure switch
SOURCE: my service engine light is
These are all things that can affect your gas mileage and engine performance.
To check for vacuum leak, look for unhooked hoses on top of engine. If OK, use starter fluid and spray along intake manifold gaskets with engine running. If engine speeds up, there is a leaking gasket.
IAC deals with idle. Does the car idle smoothly? If not, remove IAC to see if it's dirty. I will paste instructions below for the IAC valve.
Throttle body dirty--what code is this? never heard of such a code, but you can clean the throttle body wioth carb cleaner. I will paste instructions below.
IAC valve info:
Operation
The amount of air taken in during idling is regulated by the opening and closing of the servo valve located in the air passage that bypasses the throttle valve. The servo valve is opened or closed by the activation of the stepper motor (incorporated within the idle air control motor in the forward or reverse direction. Battery positive voltage is supplied, by way of the MFI relay, to the coil of the stepper motor. The engine control module switches ON the power transistors (located within the engine control module) in sequential order, and, when current flows to the stepper motor coil, the stepper motor is activated in the forward or reverse direction.
Removal & Installation
To install:
Testing
Checking Coil Resistance
Checking Operation Sound
IAC picture--mounted on top side of engine.
Throttle body--loosten clamp to right of throttle body and pull hose off. Use electric parts cleaner or carb cleaner--spray on dirt with engine running. don't touch any sensors inside throttle body--sensors are delicate.
SOURCE: 2001 Isuzu Rodeo 54248 miles
Hi.
If problem is only on startup and when idleing, then the problem is likely IAC system, also a vacuum leak will cause the same problem.
If problem is not only on startup and idle, but also when driving, then MAP sensor and EGR system must be checked.
Check also accelerator cable state and setting.
The first thing to do is pulling out the OBDII fault codes stored in the ECM. This is done connecting a code reader to the ECM diagnostic port. The job can be done for a small fee at any local garage, and it is done for free at AutoZone.
The codes will help locating the problem.
About possible faults:
Problem is stalling when idling and during startup, but engine idling fast all the time. Problem not starting at times it is due to the fact that the wrong mixture is being sprayed, this is probably causing flooding and misfire. Since the CEL is on, one of the codes returned is probably misfire.
Check accelerator.
Check IAC system. This is composed by a valve and a solenoid that check and control amount of extra air air when the engine is idling. The IAC valve is located on top of the throttle body.
Check the vacuum system and try cranking with gas tank cap off. Vacuum
system is tested using an hand tool gauge onvacuum lines while spraying
card cleaner on the hoses (or heating them with a torch). If there is a
leak, pressure will go up. A big leak will also do hissing noise, and
will often result in a lean code when doing an OBD code scanning.
This kind of symptoms can also be caused by weak wiring to MAP/MAF sensor (MAP in this engine).
If the car also drives very rough and is revving up and down in a weird way, check the EGR valve.
As first thing I would do a code scanning. This car is OBDII. The scan can be done for free at the nearest Autozone, or for a small fee at any garage.
If you get any OBDII code from the scan, report it here, so that we can individuate the possible reason for the problem.
If you repute my solution helpful, then please take some times to accept the solution. Providing good repair tips requires time and skills, and your feedback is important for us.
Regards.
Ginko.
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