5.3 Idle problems

[bigbadchev72]

Just recently since it has gotten cold outside 20 degrees and below, our tahoe has been having some problems. I went to start it the other day and it fired up and died immediatley, I fired it up again and the same thing, I can get it started and give it gas and it will run, After about a minute it will idle on its own, But its up and down in rpms.

It has 83k on it and is the new body style, yesterday I changed out what appeared to be oem plugs, wires, fuel filter, and air filter, Cleaned the map sensor, and throttle body.

Right after all this started I figured it was water in the fuel so i dumped a bottle of prestone water remover in a 1/4 tank of gas and some injector cleaner as well.

I fired it up this morning when i got home and it fired right up and stayed running went right up to 1500rpm then down to a slightly rough 1000rpm then back to 1500 for about 5 seconds then back and forth.

Where should i go from here? No check engine light is on