350 tbi knocks (rattles)

I have 1995 5.7 tbi that knocks for a few seconds on
start up. It does it in the morning after it sat up over night &
if it set up for a hour or two. It doesn't knock any after
it knocks then. What could this be?

I have 1995 5.7 tbi that knocks for a few seconds on
start up. It does it in the morning after it sat up over night &
if it set up for a hour or two. It doesn't knock any after
it knocks then. What could this be?

Check your oil level, is it low?

I have 1995 5.7 tbi that knocks for a few seconds on
start up. It does it in the morning after it sat up over night &
if it set up for a hour or two. It doesn't knock any after
it knocks then. What could this be?

sound on the internet is hard to determine cause. carbon-ed rings will do it. also some coolant could be leaking into the cylinder.. do a compression test. also pressure test the cooling system..

add 3-4 OZ of marvel mystery oil to the fuel. this is a good cleaner and helps to remove carbon deposits if used regularly. old engines will last longer as it helps keep the combustion chamber clean.

this is an oil not a solvent. very safe to use and has a record of fixing dirty engines / fuel systems for many decades.