L67 grampy car cat issue, or maybe coils?

[3repete]

I've been bringing this L67 Buick Ultra along. Looking for some input. I have already found a misfire & replaced the wires and plugs with NGK stuff. The plugs are iridium.
I get a ratcheting noise under power at higher rpm. Originally was at 4000 revs so I swapped in the coils from my other car and the ratcheting went up to 4500 rpm.
I'm thinking sure coils, but is that how these cars act when there's a clogged cat? No engine codes are being displayed, though I do have a trans problem code (PO741) that I am separately working on.
Which coils do the best? And would a voltage upgrade sometimes help? This car is loaded with power accessories.

 

[cheatah faheatah]

Ratcheting ?? Like pre-ignition (ping) ?

 

[Scottydoggs]

check for zip ties on the axles lol

for real tho vids help for sounds.

 

[cheatah faheatah]

Or playing cards in you spokes ? ... lol

 

[3repete]

Yeah, like a fast clicking under load. And nope no zip ties. I'll smack the cat to check for rattles, put in new coils and report back.

 

[Slick2500]

Yeah, like a fast clicking under load. And nope no zip ties. I'll smack the cat to check for rattles, put in new coils and report back.

Usually when the cat goes, there will be a lack of power under load, and the cel flashes.

 

[lola]

Grampy.

 

[cheatah faheatah]

Post a vid w/good sound...

 

[rynoman03]

I've been bringing this L67 Buick Ultra along.

What does that even mean??? :th_scratchhead::th_confused:

 

[lola]

I'm willing to bet the noise (since you have a transmission code) is trans related.