Hello, I drive 2007 corolla with 97,000 mile. Recently, I noticed a slight drop in RPM level while stop this sometimes caused vibration though the engine not off. What is responsible for this and what is the solution?
Run the fault codes as the engine idle is being affected by a faulty sensor . The vibrations are probably because the idle rpm's are too low.
SOURCE: Hyundai Veracruz 2007 Sudden engine
OK, folks, here's the scoop. The dealer took our Veracruz in for diagnostic testing and determined the cause of the problem was the actuator for the Electronic Transmission Control system (ETC).
Apparently, in later model cars like the Veracruz, a computer controls the transmission as well as the engine for optimum performance.
If the computer detects a severe enough fault in one of the components of the ETC (e.g. bad sensor, bad component, etc), it places the vehicle in limp home mode.
Based on my experiences, when in limp home mode, the transmission is forced to stay in 3rd gear, the engine will not exceed 2000RPM, the accelerator is not responsive past 2000RPM, and the engine runs rough (probably because the mixture is changed to very rich). The philosophy here, as was explained to me by somebody who works for Hyundai, is to allow the vehicle to continue operating long enough so that it can be driven to a safe location or for service.
I asked whether or not this limp home "feature" could be disabled at the dealership, but apparently it cannot.
I have alerted some folks at Hyundai Motor USA to this thread so they can do further research if the problem begins to affect more individuals than just us three.
FYI - I am in no way shape or form a mechanic or mechanically-minded, so if I have explained anything correctly, I will gladly accept further corrections/explanations from an expert or mechanic. :)
SOURCE: 1999 Toyota Camry Idle Problems on Hot days
Clean the IAC. Disconnect throttle body air hose and you will see a hole on the bottom of the throttle body just before the butterfly valve. Spray throttle body cleaner down the IAC hole and then let it soak about 1/2 hour. Reconnect hose and run engine about a minute and then repeat this process 2 or more times. Toyota engines from 1997-2005 commonly have the IAC get cruded up with carbon as early as 35,000 miles. This is a sImple and cheap repair that many repair shops don't want you to know.
SOURCE: 2004 subaru forester, 99,000 miles. Check engine
Drop in to an Autozone, or Pep Boys, or similar big parts store & they will usually scan for codes free. This will hopefully eliminate all the guess work, or at least point everyone in right direction for better diagnosis. If not obvious from codes what the problem is, get back to us and we'll help you out.
Testimonial: "Thanks for the great suggestion . I'll have Autozone read the codes on Monday. Thanks again!"
SOURCE: '03 Toyota Corolla 1,4 VVT-i 4ZZ engine idle rpm
Idle is factory set and cannot be adjusted, your best bet is checking for cracked hose pipework for air intake at idle,(not at problem under exceleration and driving) Any slight upset to the air /fuel ratio will be most prevelent at idle speeds.Check hoses where the meet metal flanges on manifold intakes and any sharp bends in ppipes.Good luck
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