I have a Chevy 2.8 fuel injected Blazer 2wd. and i have a loud knockin when the car is in movement, not when it idles. I thought it was a thrown rod or had to deal with the pistons but it doesn't seem to get any worse. i was told it may be a clogged oil port when i had some seals and gaskets put on they may have filled a port with silicon. I just wanted to see what may be wrong...any ideas? :/

 

Does it do it when you idle up around 3k? or just when under a load? My mothers Bonneville Did the same thing and it ended up being a loose torque convertor. Check the bolts that hold it onto the flywheel and make sure they are tight. Just an idea.

 

It doesn't when it idle really...just when you accelerate. Is that what you mean? it does when it accelerates period, doesn't matter what speed.

 

he means when the trucks in park and you race it to 3k rpms do it knock ? if not its when the trucks on a load meaning the truck is moving

 

Cracked flexplate or loose flexplate to torque converter bolts perhaps? Had a similar thing happen to my old '85 S10 pickup.

 

ohh ok, thanks. umm well it knocks when it idles up period. And when its under load. Just when it is on but not being revved up does it not knock.

 

Its either a bearing is starting to fail,or torque convertor bolts are loose.