Page 1 of 3 123 LastLast
Results 1 to 10 of 29

Thread: Revving at Idle

  1. #1
    Senior Member Gnestovia's Avatar
    Join Date
    Jul 2018
    Location
    West Virginia
    Country
    United States
    Posts
    114
    Thanks
    4
    Thanked 46 Times in 23 Posts

    Revving at Idle

    Ever since I've bought the car in 2018, I noticed when I start the car, at idle, it will rev up and down like I'm touching the gas pedal but I'm not. It did it once in a while. Here recently, it has gotten worse. It's now everytime I have started the car. Now I got an engine light saying there is a cylinder misfire. Forgot what cylinder, but when I put the car in gear, the revving stops or when I turn something on such as the AC. So I know it's definitely not the spark plugs or the wiring cause those are for sure good. So my guess is, could it be a bad coil or injector? Thanks!



  2. #2
    Senior Member
    Join Date
    Aug 2017
    Location
    SW, WI
    Country
    United States
    Posts
    7,402
    Thanks
    594
    Thanked 2,688 Times in 2,106 Posts
    Quote Originally Posted by Gnestovia View Post
    Ever since I've bought the car in 2018, I noticed when I start the car, at idle, it will rev up and down like I'm touching the gas pedal but I'm not. It did it once in a while. Here recently, it has gotten worse. It's now everytime I have started the car. Now I got an engine light saying there is a cylinder misfire. Forgot what cylinder, but when I put the car in gear, the revving stops or when I turn something on such as the AC. So I know it's definitely not the spark plugs or the wiring cause those are for sure good. So my guess is, could it be a bad coil or injector? Thanks!
    Some members have used Chevron Techron Fuel Injector Cleaner with good results. If I was having an issue, it's something I would try first.

  3. #3
    Senior Member Gnestovia's Avatar
    Join Date
    Jul 2018
    Location
    West Virginia
    Country
    United States
    Posts
    114
    Thanks
    4
    Thanked 46 Times in 23 Posts
    Thanks Mark, good thought. So, the cleaner, I wonder what is the best to buy? Brand wise?

  4. #4
    Senior Member
    Join Date
    Mar 2020
    Location
    Louisiana
    Country
    United States
    Posts
    142
    Garage empty: add car
    Thanks
    47
    Thanked 33 Times in 27 Posts
    My dad swears by techron, I haven't had an op to compare it with anything myself. I'm using lucas fuel system treatment – don't know if it's doing any good, but it's not hurting anything and I already have it, so down the hatch it goes!

        __________________________________________

        click to view fuel log View my fuel log 2017 Mirage ES 1.2 automatic: 42.3 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.8 mpg (Imp)


  5. #5
    Moderator Eggman's Avatar
    Join Date
    Sep 2015
    Location
    Cleveland, Ohio
    Country
    United States
    Posts
    10,156
    Thanks
    4,039
    Thanked 2,788 Times in 2,107 Posts
    The forum consensus goes with Techron as the favorite. Just be sure it's a fuel system cleaner, not an additive. Using fuel additives can be avoided by using good quality fuels such as Top Tier brands.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 49.6 mpg (US) ... 21.1 km/L ... 4.7 L/100 km ... 59.5 mpg (Imp)


  6. #6
    Senior Member Cobrajet's Avatar
    Join Date
    May 2015
    Location
    Olympia, WA
    Country
    United States
    Posts
    3,126
    Thanks
    1,197
    Thanked 1,848 Times in 1,101 Posts
    How many miles?

  7. #7
    Senior Member Top_Fuel's Avatar
    Join Date
    Feb 2016
    Location
    Ohio
    Country
    United States
    Posts
    3,699
    Thanks
    2,582
    Thanked 2,537 Times in 1,471 Posts
    Quote Originally Posted by Gnestovia View Post
    ...Now I got an engine light saying there is a cylinder misfire.
    ...Forgot what cylinder...
    I assume you have the ability to read/clear OBD codes in your car? Make a note of the cylinder with the misfire. Then clear the codes and see if that misfire code comes back on the same cylinder. If it does, then I'd figure out your misfire issue first. Don't start throwing new parts at it. There are some simple things you can do for free to help diagnose the problem.

    Here's another thread you may find interesting...

    Erratic RPMs at idle start up Solved with fuel system cleaner

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 52.2 mpg (US) ... 22.2 km/L ... 4.5 L/100 km ... 62.6 mpg (Imp)


  8. #8
    Senior Member Gnestovia's Avatar
    Join Date
    Jul 2018
    Location
    West Virginia
    Country
    United States
    Posts
    114
    Thanks
    4
    Thanked 46 Times in 23 Posts
    61,250 Miles, 98,572 Kilometers.

    Yes, I do have the Torque App on my Android phone this has the ability to read codes and tell me pretty much everything that is going on.

    Yeah, not worth spending money on parts that isn't bad lol. That's why I wanted to ask you all for help to see what I can do.

    I'll give the Techron Fuel System Cleaner first to see if it doesn't work. If not, I'll go from there. I do work as a Maintenance Technician at Toyota too so I'm learning haha. As always, I appreciate the time.

    I'll give an update as well after this too.

  9. #9
    Moderator inuvik's Avatar
    Join Date
    May 2015
    Location
    Coos Bay, OR
    Country
    United States
    Posts
    3,835
    Thanks
    4,761
    Thanked 1,562 Times in 1,120 Posts
    Quote Originally Posted by Gnestovia View Post
    Ever since I've bought the car in 2018, I noticed when I start the car, at idle, it will rev up and down like I'm touching the gas pedal but I'm not. It did it once in a while. Here recently, it has gotten worse. It's now everytime I have started the car. Now I got an engine light saying there is a cylinder misfire. Forgot what cylinder, but when I put the car in gear, the revving stops or when I turn something on such as the AC. So I know it's definitely not the spark plugs or the wiring cause those are for sure good. So my guess is, could it be a bad coil or injector? Thanks!
    How aggressively do you drive your Mirage? There are those that say trying a "Italian tune up" wouldn't hurt either. With the small displacement of the 1.2 I'm thinking running it aggressively from time to time definitely would not be harmful. Not that revving it up to 6000rpm on a regular basis would be advisable but a little WOT operation every now and then wouldn't hurt.

        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 automatic: 40.5 mpg (US) ... 17.2 km/L ... 5.8 L/100 km ... 48.6 mpg (Imp)


  10. #10
    Senior Member
    Join Date
    Mar 2020
    Location
    Louisiana
    Country
    United States
    Posts
    142
    Garage empty: add car
    Thanks
    47
    Thanked 33 Times in 27 Posts
    I rev mine up to 4-5k regularly just to get up above 40-50mph from a stop, still getting 42-51mpg on trips longer than a few minutes, so you don't have to worry about fuel efficiency at least. lol

    I don't do it in regular drive, though. The CVT seems to not like that too much. Switch to Ds if you're going to gas it, put it in D at around 40-50mph, or 60 if you're traveling at 70+.

    Edit: 4-5k, not 5-6k. Usually around 70-80% throttle, got plenty of horsepower and torque at that spot.


        __________________________________________

        click to view fuel log View my fuel log 2017 Mirage ES 1.2 automatic: 42.3 mpg (US) ... 18.0 km/L ... 5.6 L/100 km ... 50.8 mpg (Imp)


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •