I would be tempted to recommend a higher octane fuel & some top oil into the fuel like MMO (Marvel Mystery Oil) 4 oz per 10 gallons.
IDK what happening with all the lower Octane ethanol fuels, but they also like to absorb moisture.
MMO should help stabilize & clean injectors & rings etc...

i dont usually run fuel cleaners... once in a while i'll run mmo in with the oil, and have ran seafoam in the tank

when i replaced intake gaskets, inside the engine was exteremly clean...so about every year...i'll add mmo and seafoam

thanks for info

I agree its a bit common for old engines to knock on its first start specially in the morning due to lifter slap.

update,

I replaced the MAF sensor after getting the p0102 CEL low maf voltage

no more spark knock one cold starts

no more bogging down going up hills on interstate

fishbite chuggle while going up hills

wish the maf would have threw a code sooner, took about 6 months of symptoms before actually throwing the code/cel

the fishbite/chuggle

I've read many post about the fishbite/chuggle issue on the 3.8, while in lock-up, 70mph going up hills on the interstate you will feel a fishbite chuggle as if either the engine is surging or the transmission starts come out of lockup, but then does not...

I was getting this feeling..for about 6 months

everyone was posting they could never solve the fishbite feeling, most thinking, it was a solenoid, while others were tossing dollars into plugs/wires/coils/fuel filters/fuel pumps..etc

In my case, I had already done coil paks/wires/plugs, before I was feeling the fishbite

and for my car, the manifold air flow sensor was the issue and fix

it finnally sent a code for MAF low voltage...I cleaned it, with maf cleaner, but would just trip the check engine light again

so off to the parts store, I get a spectra new maf sensor..and install....but the the car would not idle, and again, cel..., I return the spectra unit, and swap out for a reman a1cardone unit, and has been working fine

I reset the computer to clear out all learned idles/driving habbits by disconnecting battery, and discharge by connecting cables together, and reconnect batt

and has been running perfect @ 29 mpg, and will pull hills effortlessly, with smooth delivery and much more power

I did a search on the specta maf that did not work, and found everyone else had the same issue, no idle, and returned part, I emailed spectra.. and they never reply

so, if your 3.8 is doing spark knock while cold, fishbite or chuggle while pulling interstate hills, boggy acceleration.. you may have a MAF sensor that is failing.

it will need to fail completly before making the check engine light to come on

amazing differance after replace

Thank you for the follow up.

Glad to hear you figured it out, hope it keeps running great for you!
Appreciate the update, that may help others in the future.