JeezLouiseGMC
OBS Enthusiast
Hey everyone, its been a while and it seems i only come back around when problems arise.
My truck is having a very slight misfire around 70-75mph under light throttle light load on the interstate. At times it is barely noticeable whereas others you'll feel a sudden deceleration and a pop in the exhaust. It drives perfect under 55mph with no misfires what so ever. I have no check engine light and all my vitals on the dash look great. This really doesn't affect drivability a ton but it does make me feel uneasy driving on the interstate because of this.
Shortly after this started I replaced my distributor (somewhat unrelated, had a no start condition), as well as did a tune up including new NGK plugs and wires, and replaced my ICM with an AC Delco unit.
The coil is also fairly new, having been replaced a year or two ago with an NGK unit.
I was reading on another thread that it could be the EGR valve being clogged up and that's my next step. I would like to know if anyone has had a similar issue and what their fix was?
Thanks for your help in advance!
1999 Sierra Classic, k1500 Vortec 5.0.
My truck is having a very slight misfire around 70-75mph under light throttle light load on the interstate. At times it is barely noticeable whereas others you'll feel a sudden deceleration and a pop in the exhaust. It drives perfect under 55mph with no misfires what so ever. I have no check engine light and all my vitals on the dash look great. This really doesn't affect drivability a ton but it does make me feel uneasy driving on the interstate because of this.
Shortly after this started I replaced my distributor (somewhat unrelated, had a no start condition), as well as did a tune up including new NGK plugs and wires, and replaced my ICM with an AC Delco unit.
The coil is also fairly new, having been replaced a year or two ago with an NGK unit.
I was reading on another thread that it could be the EGR valve being clogged up and that's my next step. I would like to know if anyone has had a similar issue and what their fix was?
Thanks for your help in advance!
1999 Sierra Classic, k1500 Vortec 5.0.