Rough idle

Asked by Connie Mar 27, 2016 at 10:35 PM about the 1991 GMC Sierra 1500 C1500 SLE Extended Cab LB

Question type: Maintenance & Repair

Rough idle won't stay running have change
elec.spark control, idle air control,plugs,map
sensor,tps, and the ecm.. Still running rough but if
you unscrew the IAC it idles high but the miss
smooths out...I am at a loss any ideas

12 Answers

80

My car is a 2005 chevy aveo it. Stalls out when take off oil light blinks off and on what could the problom

940

Almost sounds like it's missing. Have you changed the spark plug wires? I would pulling by one answer if you notice a difference. Could have a bad wire. Sounds like a timing issue.

940

Pull your cap if you not changed it. Check inside it. See if you see white lines on the inside. Best describes and white lightning marks. Could be bad cap that's causing a misfire.

940

Sorry I was answering the questions. Above for this forum. But have you checked to make sure you have oil?

940

My rule of thumb is always check fluids and change oil when buying a used Alvarez that is not certified.

Pull throttle body, easy to do, clean w/ carb and choke cleaner using a nylon brush only. Makes a hell of a difference.

Your Answer:

Sierra 1500

Looking for a Used Sierra 1500 in your area?

CarGurus has 7,258 nationwide Sierra 1500 listings starting at $3,950.

Postal Code:

CarGurus Experts

  • #1
    yetilikesbeer
    Reputation
    12,830
  • #2
    dragonflyoffshore
    Reputation
    11,750
  • #3
    John Saffrahn
    Reputation
    11,690
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Ford F-150
321 Great Deals out of 14,968 listings starting at $1,712
Used GMC Yukon
16 Great Deals out of 929 listings starting at $1,225
Used Chevrolet Corvette
29 Great Deals out of 1,060 listings starting at $15,871

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.