If you have a sludge problem , Use a quart of MMO in the oil with a good cleaning oil like
PYB. Go to a 1000 oil change. Then go with another cleaning oil like M-1 and a good filter and a 3000 mile change. I did this in a 2000 Monte Carlo with a 3.4 . After 2 cycles , the sludge was pretty much gone.
If its carbon , use GM top clean.
Don't use quick cleaners. Just asking for problems.