engine shudder @ about 42 mph and engine misses

[lsdriver007]

I have read many previous threads about ls engine misses at low throttle around 40+ mph. I originally had a code for excessive egr flow, so I just replaced the egr valve and the dpfe sensor, and no further codes but still the misfire and engine shuuder. I have had my 2002 v8 ls for 5 years and still just 83,000 miles, and have replaced a few of the coil packs, but have always had a code thrown for each failed coil previously. This time no code for the bad coil, so I finally tested each coil individually using a basic spark tester inline after changing all the plugs, and found one of the coils dead with no spark...replaced that coil, and it's a new car again. I had also been smelling the bad egg sulfer smell after driving prior to changing out the bad coil...all is good again. I hope this can help anyone who was experiencing similar issues. Have a good day Chris.

 

[joegr]

You'll be doing this all over again in a month or two, maybe less. Experience here has been that it's best to go ahead and replace all the COPs at once. You did replace the spark plugs with the coils, right?

 

[chocolat1701]

yup once one goes replace all of them.