Q: 1.6 d16y5 engine idled high like 4k so i tested the iac and that was replaced, starts&runs fine, then idles up&down when warm?Y?

asked by on February 08, 2018

Tested iac after I started it up in the morning for work and idled to 4k and then stayed at 3k for a bit then eventually idled down so that tested to be bad and was replaced, then next day it was fine, then the gauge stopped working a week later, so I tested the ECT SENSOR with my multimeter and that was bad so I replaced that and the gauge worked for like a day and now works once in a while but makes me nervous not knowing what the temp is, but now when I start the car it idles to 2k then comes down to 1500 and then once it warms up to operating temp that I can see when the temp gauge is working it starts idling up and down from 1k to 2k rpms and doesn't stop and then the gauge usually drops to nothing like the very bottom, if any other details you think could be helpful. Let me know, thank you!!!!!

My car has 106000 miles.
My car has a manual transmission.

Engine idle speed is high Inspection $94.99 - $114.99 Get a Quote

A faulty or blown fuse in other electronically controlled systems can cause the IAC (idle air control) motor to malfunction, leading to a higher than normal engine idle speed. Other possible causes of a high idle include vacuum leaks, a malfunctioning throttle (throttle plate could be sticking; throttle position sensor could be faulty) and, rarely, a PCM/ECM malfunction. With regard to vacuum leaks, on a fuel injected engine a vacuum leak will cause a high engine idle as the engine’s oxygen sensor detect the extra oxygen entering the engine through the vacuum leak. The newly lean (too much air relative to fuel) status will result in the engine’s computer pumping in additional fuel, resulting in an abnormally high idle. If you desire that this high idle problem be diagnosed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an engine idle speed diagnostic - high idle and the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Accelerating causes ticking noise.
A ticking noise indicates a worn valve lash adjuster that is dirty and needs cleaning or needs to be replaced. These are the lifters that ride on the camshaft and provide lift for the valve. They are spring loaded and...
ABS light goes on and off when driving at low speeds
The most common cause of the pedal becoming hard is due to the power brake booster failing (https://www.yourmechanic.com/services/power-brake-booster-replacement). The brake booster can cause the ABS faults as well or it could be something different. A qualified technician like one from...
Brake lights
If you did not check the bulbs themselves before changing the brake light switch, you might want to start there. Blown brake light bulbs (https://www.yourmechanic.com/services/brake-light-bulb-replacement) can actually cause the ESC light (https://www.yourmechanic.com/services/brake-warning-light-is-on-inspection) to come on, so make sure that the...
Car will not start but the dash lights turn on.
Often when a battery has a bad/damaged cell internally, it may not accept a jump start. The easiest thing to do would be to replace the battery (https://www.yourmechanic.com/services/battery-replacement) with a known good battery, whether temporarily swapping one from another vehicle...
Can you use a California emission fuel pump or will federal fuel pump work
Depending on your state, this should normally not be an issue as a California fuel pump and Federal fuel pump both run the same amount of fuel pressure. The issue is whether or not you live in California. If you...
what to do with so de mirror camera
I would imagine that the camera is supposed to be mounted to the rear view mirror as a dash cam. Dash cams are good in the event that you are involved in an automobile accident or if someone attempts to...
My 99gmc suburban backfires in the throttle body, won't start.
If you were getting a rattling noise in the lower front of the motor then you engine may have jumped timing. The timing chain may have been so worn that it jumped ignition timing between the crankshaft and camshaft. That...
When car is off and in park I can turn the wheel left and right and makes a clicking/clicking noise.i have changed both ball j LRT
The noise will be most easily pinpointed if you have an assistant turn the wheel while you, or a mechanic, hone in on the location. There are quite a few other potential sources of the noise such as the upper...
my bank 1 sensor 2 has been replaced and check engine light still comes up. i have also changed my catalyst converter, and my car
Hi there. Unfortunately, these type of issues are incredibly complex to pinpoint and isolate the root source of the problem. Typically the best way to complete the diagnosis is to have a professional mechanic start by completing a check engine...

Related articles

A Buyer’s Guide to the 2012 Honda CR-Z
In In the tradition of the sporty CRX, the CR-Z boasts some of the similar look, without quite the same amount of pep. That’s because the CR-Z is Honda’s eco-friendly offering and a pretty unique one to boot – (as...
The Best Used Cars to Buy If You’re an Athletic Coach
If If you are an athletic coach, you need a used vehicle with tons of room to transport gear. Once in awhile, you may have to take a player or two along with you as well. What this means is...
The Best Used Cars to Buy If You’re Shorter Than Average
Vertically Vertically challenged? Hate getting behind the wheel and having to crane your neck to see? There’s nothing wrong with you, but there is something wrong with your car. It might be time to trade it in and take advantage...