running on 7

HI GUYS I HAVE A 1999 GMC SIERRA Z71 WITH A 5.3 I DID EVERY THING TO IT,LIKE THE WHOLE TUNE UP ,ENGINE LIGHT COMES ON ,TAKE OUT MY OTC READ THE CODE IT SAYS MISFIRE ON 4 SO I CHECK ,I CHANGE THE PLUG, WIRE,AND THE COIL PAK ,RUNS FOR 5 MINUTES AND BANG IT SHOWS UP AGAIN ENGINE LIGHT I READ AND SAME THING AGAIN ,ANY ONE HAD THIS BEFORE NEED HELP PLEASE...........:banghead:

Are you sure the #4 plug is firing? If you have a timing light you could use that to check or use a sparkplug that is grounded.

It could also be an injector issue since a misfire can be lack of spark or lack of fuel.

Also make sure you have compression in #4.

//2000CAYukon

hey buddy i did not forget to answer u bac it just i work at nite and didnt have time to look more into it ,but i did change the coil ,spark plug and wire again ,only on the #4 and still does the same ,i did look for gas leak from injecters but dry and ill take the pressure on friday im off have more time ,and if it stops raining here i could ride my harley to work lol lol save gas ....

well mr.2000cayukon i just want to let u know i work on the truck all weeken and guess what ,,,,the problem was the coil pack connector plugs they were loose ,still loose i have to change then all ,but once pluged in my baby is back alive ,i just want to thank you sir for ur help ,,,if ever ur in montreal beer is on me ,,thank again

well mr.2000cayukon i just want to let u know i work on the truck all weeken and guess what ,,,,the problem was the coil pack connector plugs they were loose ,still loose i have to change then all ,but once pluged in my baby is back alive ,i just want to thank you sir for ur help ,,,if ever ur in montreal beer is on me ,,thank again

Glad you got it fixed. Don't know when I will be in Montreal, but when I am I will take you up on a beer or two!!

//2000CAYukon