why does my truck shut off when idleing

Asked by danfield70 Sep 19, 2012 at 02:58 AM about the 2003 Chevrolet Silverado 1500 LS 4WD

Question type: Maintenance & Repair

when pressure is applied to the gas pedal, it runs fine but as soon as i take my foot off it starts to bogg down and shuts off. check engine light is not on and it now has trouble starting up

1 Answer

69,075

May be a vacuum leak a bad idle air control or a bad fuel pressure regulator. Since it won't idle it will be hard to check the idle vacuum. Start with the fuel pressure regulator. You will need a fuel pressure tester and a vacuum gun. Hook up the fuel pressure tester and turn the key on. Pressure should be around 60ish PSI, apply 15-20 inches of vaccum to the pressure regulator. The regulator should hold that vacuum till you let it off, and the fuel pressure should drop to 40-45 PSI. If it doesn't drop then the regulator is flooding the engine at idle. Replace it. If that tests good then pull out the idle air control and give it a good cleaning with carb cleaner and check for movement, reinstall and check how it idles. If it still idles bad then get a vacuum diagram and one by one remove the vacuum lines from the manifold, plug the hole with your finger, and have a friend start the truck. STAY CLEAR OF MOVING PARTS. Wear short sleeves no baggy cloths ties or necklaces tie up long hair if applicable. If one of them being removed allows the truck to idle then find the bad spot in the line or bad part and repair it. If neither of these work then the problem is quite possible a leak at the manifold somewhere or a burnt valve an injector stuck open and the list guess on. Try these easier steps first and let me know how it goes.

7 people found this helpful.

Your Answer:

CarGurus Experts

  • #1
    Rowefast
    Reputation
    10,400
  • #2
    John Carson
    Reputation
    9,580
  • #3
    Andrew Olsen
    Reputation
    9,450
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used GMC Sierra 1500
143 Great Deals out of 7,815 listings starting at $5,500
Used Ford F-150
319 Great Deals out of 13,512 listings starting at $3,888
Used Chevrolet Silverado 2500HD
21 Great Deals out of 1,571 listings starting at $5,990
Used Toyota Tundra
36 Great Deals out of 918 listings starting at $10,698
Used Toyota Tacoma
41 Great Deals out of 786 listings starting at $9,975
Used Dodge RAM 1500
80 listings starting at $5,000
Used Chevrolet Tahoe
18 Great Deals out of 779 listings starting at $7,499
Used Chevrolet Colorado
44 Great Deals out of 1,142 listings starting at $4,995
Used GMC Sierra 2500HD
32 Great Deals out of 2,112 listings starting at $8,490
Used Ford F-250 Super Duty
28 Great Deals out of 750 listings starting at $3,990
Used Chevrolet Camaro
15 Great Deals out of 465 listings starting at $11,999
Used Ford Mustang
35 Great Deals out of 1,603 listings starting at $7,999
Used Chevrolet Corvette
15 Great Deals out of 777 listings starting at $18,999

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. Content will be removed if CarGurus becomes aware that it violates our policies.