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 GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 15201
Experience:  GM Grand Master Technician 2007. 14 years experience.
Type Your Chevy Question Here...
GM Tech (Cam) is online now
A new question is answered every 9 seconds

2007 GMC Sierra vortec max rough idle. Runs fine under load

Customer Question

2007 GMC Sierra vortec max rough idle. Runs fine under load but shudders at low idle or when in Park.
JA: Is the rough idle intermittent or consistent?
Customer: Consistant. Mech says the fuel injectors are working properly. Just completed new plug/wire change due to mileage (114,000) but issue still exists.
JA: Are you fixing your Sierra yourself? What have you tried so far?
Customer: I'm old school mech- not up to snuff for modern systems. I do routine maint and use a ASE certified mech for anything else. Plugs, wire, even tried swapping coil packs between cylinders- nothing changed so went back to original configuration on packs
JA: Anything else you want the mechanic to know before I connect you?
Customer: Have been told by one garage I need a complete valve job on engine ($3000 minimum)another says to re-flash the computer at a dealer
Submitted: 10 months ago.
Category: Chevy
Expert:  Jared D replied 10 months ago.

Any time we see one of these trucks in for a rough idle it's almost always caused by bad lifters. They get gummed up and need to be replaced all the time.

Are you getting any trouble codes?