cold engine acceleration knock on my 96???

[Black Ice]

I have a slight knock on on acceleration when my car is cold. I hear nothing at cold idle also nothing at all even on acceleration when the coolent is 140 degrees or higher. This seems to happen if I dont let the car "warm up" and is like a metallic tapping sound any ideas anyone?

 

[dmrodco]

I think you just answered your own question ....... A tapping, small block chevy's have always had a weekness in the cam area less so with the rollers but my first thought would be a sticky lifter. Second might be the knock sensor giving faulty info to the ECM. its my 2 cents worth and a place to start looking anyway. :J

 

[Black Ice]

Well it really sounds to me more like a spark knock. Im just wondering if it could be a bad plug or clogged injector or maybe even a bad plug wire. Just dont know if any of these could be temp sensitive

 

[Alex D]

This is actually very common to the Chevy small block. Some engines have more of it, some less. it's piston slap. When cold the pistons rock a little in the bore and make the noise. This really sounds bad and the knock doesn't sound that good either, put it actually hurts very little and goes away very soon after starting on most cars

I have a slight knock on on acceleration when my car is cold. I hear nothing at cold idle also nothing at all even on acceleration when the coolent is 140 degrees or higher. This seems to happen if I dont let the car "warm up" and is like a metallic tapping sound any ideas anyone?

 

[compyelc4]

This is just a wag with the info you've given us, but I'm betting on piston slap too. About 1/2 the late model GM V-8's I've had experienced some degree of that..........all the way past 140K! I would not be too concerned about it. Just let her warm up a bit before backing down the drive. She'll be alright.

Ted