My Car's Rpm moves up and down during idle. What would cause this?
Vacuum leak !!! When vacuum leak it will cause the engine speed to go hight. Then the ECU see that it will shut the gas. Then when the RPM go low again it let gas in and the RPM go high again.
Why do cars idle at 1000rpm?
Most engines don't idle at 1000RPM. Most idle substantially lower than that. And they idle at the lowest speed possible for the particular design of the engine, including internal engine weight, number of cylinders, etc. Their idles are also configured around the smoothness characteristics of the engine at low, unloaded speed (ie, its not generating power to move the car). Lower idles consume less fuel ( in most cases, but not all), and should in theory produce less noxious emissions (which happens to not always be true). Luke is correct in that many idles are determined based on noxious emissions and associated regulations, but the differences tend to be minor in many cases from an idle speed perspective.Newer designs are actually eliminating the idle cycle in many cases, with stop start cycles appearing on more and more engines from many manufacturers these days.
How many RPMs should my car idle?
Every type of engine will idle a bit differently, so this question is impossible to answer.Smaller engines seem to idle a bit higher (700-900RPM) than larger engines (my 1995 Chevy Suburban with a 5.7L V8 idles smoothly around 500-600RPM when it's warmed up, but my 2007 Chevy Colorado with a 2.9L four cylinder idles at about 700-800RPM when it's warmed up).Most cars idle higher when they are just started in the morning and the engine is still cold, and it settles down as the engine warms up to operating temperature.Also, the engine idle might change ever so slightly based on whether or not the A/C is on or if you are in Drive/Reverse rather than Park/Neutral.On all modern engines (since the late 80s) the idle RPM is computer controlled while on older cars with carburetors you can manually adjust it.You might want to find an online forum specific to the type of car you have. Just google the make and model of your car and forum. There will be many members with similar vehicles that could probably tell you normal idle speed for that year, engine size, etc.
My car usually idles at 850-1000rpm. Immediately after I do a pull or something full throttle to redline, it idles at 700-800rpm for about 30 seconds before returning to the normal range. Is this a problem?
Are you getting codes? If not, then no.As Tim Boardwell said, this is a the ECU doing its job. It has a set of tables that it uses to set different parameters like idle speed, mixture, timing, advance, etc…and tables tell it to act under certain conditions.When the conditions vary, the system has to audit the information it is receiving from various sensors before “deciding” what settings are optimum. During this period, it may go to a preset value on idle and mixture that it “knows” is safe, but may not be optimum.
Symptoms of a bad idle air control valve. will it cause a car to backfire under hood or give off misfire codes?
The IAC would cause a rough idle and low rpms at idle. The misfire(s) are a different problem. If it's random misfires that jump around from one cylinder to another (read: P030x codes), it also will set a P0300 code. The cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open.
Please help. car overheats and idle high?
My Diagnosis to your situation/problem would to do the following; Overheating? - For the overheating situation, it best to check your water level by checking the radiator or filler bottle (in some models), Is the vehicle leaking any fluids?, - check all hoses and lines for splits, frays, cracks, melted or any signs of damage and replace if needed ... Also another solution would be to check your Water Pump for any faults and replace and/or repair if needed, as it may not be pumping water through and causing a block somewhere, ...(make sure you keep all your oil & waters filled up, and that you are using the recommended oil & fuel suggested for the engine, and check the levels before and after a drive) ... High Idle? - OK, for high idles, there only a few small tweaks that contribute to the idle problem ... Firstly, Adjust the idle screw, turn it down to a nice idle at about 500-800rpm, if no change, then check your ECM chip (if you have one) to make sure it is controlling your rpm and electric readings correctly ... then if no change it can only lead to one more optional solution .... Accelerator/cable problem! ... check your accelerator cable for smooth sliding and that it is not jammin' or sticking and making sure that when you release the pedal, the cable stretches out all the way, in some cases the throttle cable will jamm and have the vehicle idle high ... if still no change in performance ... it will be safe to say, you have a serious and complicated problem on your hands and you will need to take the car to a mechanic shop for further Analysis ... GOOD LUCK!
Should I idle my car in the winter? If so, for how long?
No. Letting your car idle is completely unnecessary.It’s actually better for the engine if you drive off straight away. A typical car idles at about 800rpm. It could take at least 5 minutes to let it warm up with such a low idle.If you pull away slowly and drive while keeping the rpm’s below 2500, the engine heats up much faster, and makes up for the extra rpms.When you’re driving the car is injecting more fuel, and more powerful combustion cycles occur. This generates more heat and the engine can warm up faster. Also keeping the rpm’s closer to 2000 will add negligible engine wear, and will get the car up to operating temp in a couple of minutes.Of course if you live somewhere in temperatures below -10 degrees celcius, it would not be ideal to heat the engine up too fast, as it could cause mild damage. In this case letting it idle for a couple minutes would be enough.
Why is my car's RPMs low while idle? (no engine check lights)
If your car is idling just fine and not shaking, there should nothing to worry about. For a passenger-car engine, idle speed is customarily between 600 rpm and 1,000 rpm. For buses and trucks it is approximately 540 rpm. It is more one your engine being relaxed by being uncoupled with drivetrain. If you have some accessories working on your car like air conditioning, rpm will be higher to produce enough to operate them.But if the idling is very low, common reasons include vacuum leaks, carburetor problems(for old cars), ignition issues, damaged power circuits and dirty fuel injectors. When a vehicle idles low, the vehicle stalls or shakes excessively when the brakes are activated, and this is an indication of a serious engine problem.
Car jerks/jumps when put in drive. what could be the cause?
If you do not know anything about car: First thing is to check the transmission fluid level do check when it's at idle speed, the transmission has to be in PARK position. Check the other fluid levels as well. Get some help if you don't know how. The first thing is to have the transmission fluid service, this mean the fluid and the filter has to be replaced for the transmission. Use Honda fluid ONLY; Using other fluids will do some damage or severely ruin the transmission. The second thing could affect the jerking when put in gear is the Throttle Body (TB) dirty and need cleaning. A vacuum leak could cause the erratic idle will have the same effect when put in gear. That is all I can advise you to do. Get someone who know how or at least use to "Tinkle" with car and help you out. Send a message and I'll reply if more help is needed. HTH
Toyota camry idle adjustments?
try having the throttle body cleaned,followed by an induction system cleaning,that starts at the trottle body.if that does not work,you will need to have the idle air control vavle replaced.it is under the throttle body,where the accelerator cable hooks to the throttle valve.the idle is non adjustable.changing it would be a mistake.turning the set screw might help,but it will not solve the problem.it would get worse and do the same thing later. if a mechanic is willing to spend some time on it,he can free the IAC,spray a cleaner in it and let it sit.start engine and repeat until better.