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 Dr.Automotive Your Own Question
Dr.Automotive
Dr.Automotive, Auto Mechanic
Category: Chevy
Satisfied Customers: 3803
Experience:  Automotive Degree Dealer Experienced
49697172
Type Your Chevy Question Here...
Dr.Automotive is online now
A new question is answered every 9 seconds

2008 CHEVY 4.8 / MISFIRE #4 AT IDLE ONLY / INJ.

Resolved Question:

2008 CHEVY 4.8 / MISFIRE #4 AT IDLE ONLY / INJ., COIL , PLUG & WIRE REPLACED
Submitted: 5 years ago.
Category: Chevy
Expert:  Dr.Automotive replied 5 years ago.
Welcome to Justanswer, My name isXXXXX am here to help.

Have you checked the compression on that cylinder?
Customer: replied 5 years ago.
YES 145LBS
Expert:  Dr.Automotive replied 5 years ago.
Have you checked the coil making sure its producing spark and also checking the injector making sure it has pulse putting fuel into the cylinder
Customer: replied 5 years ago.
YES / AGAIN ONLY AT IDLE / WITH A LITTLE MORE RPM'S / GOES AWAY
Expert:  Dr.Automotive replied 5 years ago.
Check for vacuum leaks on top of the intake. Spray a flammable mist under the intake while observing the fuel trim numbers and idle quality. During the misfire, place a dollar bill against the tailpipe. If the dollar bill gets pulsed back inside the pipe, check for a problem with the valve train. You either have a vacuum leak or intenal valve train problem possible it can be a valve full of carbon. Thanks

Danny
Dr.Automotive and other Chevy Specialists are ready to help you