on my 2011 3/4 silverado hd, I have a yellow engine light on. The codes are 174 and 496. MAP and o2 sensor. The only sysmptoms I'm getting are when the fuel cap is removed ther is a vacuum whoosh. The the vehicle is hard to start. Sounds like the evap purge valve. Not sure but never had one cause a vacum. Ive seen pressure, so i guess it could go the other way as well. help

Asked by Mar 30, 2016 at 07:56 AM about the 2011 Chevrolet Silverado 2500HD LTZ Crew Cab 4WD

Question type: Maintenance & Repair

2011 Chevy Silverado HD 3/4 ton

2 Answers

44,425

If your EVAP purge valve is bad, it should have also thrown a code. If you would like to test it yourself follow the link below. A hard start is a symptom of a bad purge valve, especially after you fill up at the pumps. http://www.samarins.com/glossary/purge-valve.html

1 of 1 people found this helpful.
44,425

You may want to first repair your error codes before pulling your purge valve to test it. A bad MAP sensor will cause fouled plugs and a rich fuel mixture which could be the cause of your hard start issues. Fix the codes first, then check your purge valve.

Your Answer

Chevrolet Silverado 2500HD Experts

  • #1
    Steven Loeffler
    Reputation
    540
  • #2
    Tom Demyan
    Reputation
    360
  • #3
    piocon
    Reputation
    310
View All

Related Models For Sale

Used GMC Sierra 2500HD
126 Great Deals out of 14,936 listings starting at $3,259
Used Chevrolet Silverado 1500
2,716 Great Deals out of 158,224 listings starting at $1,850
Used Ford F-250 Super Duty
433 Great Deals out of 47,782 listings starting at $1,700
Used Chevrolet Silverado 3500HD
121 Great Deals out of 11,494 listings starting at $8,800
Used Dodge Ram 2500
162 Great Deals out of 5,430 listings starting at $2,999
Used Ram 2500
203 Great Deals out of 32,782 listings starting at $6,500
Used GMC Sierra 1500
1,100 Great Deals out of 61,833 listings starting at $1,295
Used Ford F-150
3,062 Great Deals out of 230,783 listings starting at $1,300
Used GMC Sierra 3500HD
72 Great Deals out of 4,995 listings starting at $8,000
Used Ford F-350 Super Duty
397 Great Deals out of 27,118 listings starting at $3,900

Used Cars For Sale

2018 Chevrolet Silverado 2500HD For Sale
17,233 listings starting at $27,480
2017 Chevrolet Silverado 2500HD For Sale
10 Great Deals out of 2,010 listings starting at $26,977
2016 Chevrolet Silverado 2500HD For Sale
42 Great Deals out of 1,829 listings starting at $22,225
2015 Chevrolet Silverado 2500HD For Sale
99 Great Deals out of 2,569 listings starting at $14,750
2014 Chevrolet Silverado 2500HD For Sale
19 Great Deals out of 693 listings starting at $16,900

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.