It's ok, but just because it makes a smoke show doesn't mean anything. I know a way to get your engine a lot cleaner.
Start by being sure to clean the MAF with electronic parts cleaner. Brake clean is cheaper, and will work, the the electronic cleaner will leave no residue, you won't be able to even smell it after it is done.
Take tb cleaner and a toothbrush and get the TB clean. Take off the IAC and clean it out too.
Take TB/Intake/Carb cleaner (carb best/strongest) ant put it down a vaccume line, the canister purge line is a good one, get one that gets most of the intake and all cylinders. Get something to pressurize like a garden sprayer and go through the TB if possible. One good thing is our motors will run with the MAF off, and these cleaners will come in a spray can. Run the engine and hold at 2000--3000rpm and spay cleaner through the TB.
Let motor cool.
Remove spark plugs and put in a liberal amount of carb cleaner in the cylinder, but top engine cleaner is a really good one. Put plugs back in and let sit overnight. I usually put some in, run it out (no plugs in, just to splash it around) then put more in, put plugs in, then leave overnight. (finger tight plugs)
Go to bed.
Next day, pull plugs back out, spin motor over to get all that crap out. Put old plugs in, and start the motor. It may be hard to start, cold motor soked in cleaner, but it will. Run for a few minutes and get that crap out. Change the oil, and put in new plugs.
I work at a GM dealership and thanks to reverse flow cooling, we get a lot of carbon buildup which defeats the bennifits and causes the engines to knock. They have used seafoam, and many other treatments. Sometimes they make a difference, sometimes they help, but this procedure I have told you DOES THE JOB COMPLETLEY EVERY TIME. You will actually see the disolved carbon spay out of the plug holes. AND you will get a smoke show on startup, so you won't be missing anything seafoam offers.
You might want to get a towl over the plug holes because the carbon will come out and get on the exaust manifolds/headers and takes forever to burn off, it usually doesn't it will just bake on.