How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Neal Your Own Question
Neal, Chevy Mechanic
Category: Chevy
Satisfied Customers: 8349
Experience:  Shop Owner and Mechanic on multiple makes.
Type Your Chevy Question Here...
Neal is online now
A new question is answered every 9 seconds

Chevrolet Monte Carlo LS: at idle my 1986 monte carlo luxury

This answer was rated:

at idle my 1986 monte carlo luxury sport 305 runs great. when it idles for a while the service engine soon light comes on. then when i hit the gas, alot of light blueish to whitish smoke comes out the exhaust for a short while and the service engine soon light goes out. what causes this? its almost like there is not enough pressure to push the exhaust out at idle.

Hello I'm Neal and I am here to help resolve your issue. If I cannot help I will opt out and refer your question to another expert.


It is most likely just the idle air control valve that is bad and it is making it load up and get rich when idling. I would definitely try another IAC valve first. You can try just cleaning it but it does not always work.

Customer: replied 3 years ago.

i meant to add this to the original question but the codes it is pulling are 13 and 24. I don't know if this make a difference to your answer, but I have changed the O2 sensor twice with the same results. Now i will look up the IAC valve and see what this is about. Thanks

The 12 is just showing the system is working, the 24 is for the speed sensor. That is likely unrelated, usually the IAC will not cause a code, so I would still be looking at it first.
Neal, Chevy Mechanic
Category: Chevy
Satisfied Customers: 8349
Experience: Shop Owner and Mechanic on multiple makes.
Neal and 5 other Chevy Specialists are ready to help you
Customer: replied 3 years ago.

code 13 not 12.

That is showing a bad o2 sensor or a wiring issue going to the sensor.
Customer: replied 3 years ago.

I was told that my carburetor does not have an IAC value.

I thought you had fuel injection which is what they typically had that year. Based on that additional information you will likely just need to have the carburetor rebuilt.
Customer: replied 3 years ago.

all 305 V8 engines for monte carlos were carburetors from 1986 to 1988. further, it is a recently rebuilt carburetor on my vehicle. l would like a refund please.

My mistake I misread your year or mixed it up somehow after reading your first post. Has it done this since before or after the carb was rebuilt?
Customer: replied 3 years ago.

It has done this since before the carb was rebuilt.

Does it smoke when you start it after sitting for a day or longer? How many miles on it?
Customer: replied 3 years ago.


Then it might just be bad valve guides, especially if it smokes after sitting. Based on all you have told me, this would seem to be the most likely problem.
Customer: replied 3 years ago.

I'm really not happy with this answer as it does not fully address my initial question. Once again, I would like a refund. I do not want another technician or my current technician to try to answer further.

Customer: replied 3 years ago.


Sorry I could not help. I will opt out.
Contact customer service to get your deposit back.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
< Previous | Next >
  • I was having a terrible problem with the wheel bearings on my 98 Chevy Cavalier and I suspect that using this website saved me plenty of time and money. Todd L Rochester NY
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland

Meet The Experts:

  • GM Tech (Cam)

    GM Tech (Cam)

    Chevy Technician

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years experience.
< Last | Next >
  • GM Tech (Cam)'s Avatar

    GM Tech (Cam)

    Chevy Technician

    Satisfied Customers:

    GM Grand Master Technician 2007. 14 years experience.
  • Tim's Auto Repair's Avatar

    Tim's Auto Repair


    Satisfied Customers:

    Have owned a repair shop for 25 yrs.
  • Gary's Avatar


    Chevy Technician

    Satisfied Customers:

    15 years GM master tech
  • Dave Nova's Avatar

    Dave Nova

    Chevrolet Technician

    Satisfied Customers:

    ASE Master Certification. GM World Class Certification
  • John's Avatar


    Master A.S.E Automotive technician

    Satisfied Customers:

    A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
  • Don 'Mo Lurch''s Avatar

    Don 'Mo Lurch'

    Auto Mech / Electronics

    Satisfied Customers:

    Chevrolet Cert., Heavy Line Mech, Race Shop Owner, Mobile Electronics.
  • Ron Z.'s Avatar

    Ron Z.

    - Chevy Tech -

    Satisfied Customers:

    18+yrs experience. State Inspector and Chevy Diagnostics

Related Chevy Questions