Knock or backfire?

[Jjbiskup]

I have a 305tbi and when it revs high it sounds exactly like a rod knock. My donuts for the Y pipe are basically non existent. Is it a backfire caused by valve float or is it something else. It makes the noise while in gear but also when its in park and i rev it. It follows after with no power or extreme power loss.

 

[RichLo]

What RPM are we talking about? Old worn out TBI's dont like to rev past 3500rpm. And depending on the year, the rev limiter is valve float.

 

[Jjbiskup]

What RPM are we talking about? Old worn out TBI's dont like to rev past 3500rpm. And depending on the year, the rev limiter is valve float.

Its a 94 305 tbi with 230k miles. Doesnt burn oil or anything and it wasnt doing this before somebody pulled apart my Y pipe and the donut disappeared.

 

[GoToGuy]

Just state if there missing or not. Fix it, lt could part of the problem. Exhaust with leaks can allow outside atmosphere to create operating issues.

 

[Jjbiskup]

Just state if there missing or not. Fix it, lt could part of the problem. Exhaust with leaks can allow outside atmosphere to create operating issues.

Thanks, will do and ill get update once done.