I drove Camaro today, No problems oil pressure good, there's a long down hill part. I let off the gas pedal and it started rumbling and backfiring allot.
got it home and the left side lifters extra loud. I'll pull apart and inspect rockers and and springs soon, Any ideas would help

 

Exhaust leak

 

^^^^Yep! Another vote for that. Check the exhaust first or you are wasting your time. And unfortunately they usually come up exactly where you can't see them without pulling it apart a bit.

 

I'll check exhaust, But I don't think that's going to be it. It's slip joints with 3" band clamps. Thanks.

 

Could be bottom of exhaust to head gaskets as well. Always possible it might be something else but good to get the easy stuff out of the way.

 

When you lift from the throttle above a certain RPM, in most engines, there should be a 100% fuel cut. The engine is supposed to coast "engine brake" with air only (no gas). If, during this time, you are getting any kind of ignition (explosion) pops and backfires, that is a diagnostic clue that fuel is entering the cylinder somewhere (leaking injector).

 

Makes sense, Was a fubar day Friday was going to endodontist for reroot on a tooth that couldn't wait till Wednesday, I had a hard time getting it into reverse. shifting into first was harder than usual, then on way back the popping and back fire started. All in all pretty shitty day, thanks Ill check it out