99 Yukon idle

I have a slight rough idle so I pulled the pre and post o2 sensors on both sides to see what they looked like. They are coated with a white residue. I had to replace the lower intake gaskets awhile back so I assume the white is from the coolant leak. The truck has 130,000 miles.

I am debating replacing the o2 sensors all around. I plan to keep the truck for awhile, and I have heard replacing these will help with gas mileage as well.

Suggestions are appreciated.

yes if they are bad you will get bad mpg. usually the check engine light will come on and run like crap. you didnt say if you changed plugs wires cap rotor when you did the intake. pcv air cleaner mas tps, could be anything. try can of seafoam in gas, may help. i seen it fix rough idles before

No check engine light. I have replaced plugs, wires, dist cap, rotor, pvc valve, air filter.

The idle is not bad, I haul a boat and it seems the truck should have a little better pep than what it has.

Is an 02 sensor something you wait for it to go out... Or, is it common and helpful to replace at the suggested intervals? These are the originals and the truck has 130K on it.

Any suggestions on brand. I can get some Oreilly's brand through a family member for 1/3 of the Ac Delco cost.

Dave

those lil 10 bolt rears dont like pullin but thats another thread lol my 99 has plenty of pull but i'm compairing it to the 4.3 i had before.

i dont replace them unless bad, boogers are expensive. far as Oreilly's never bought from there. if they anything like advanced, i would only by mud flaps or air fresheners. get what ya pay for in parts. ac/delco is always best but i usually use napa gold stuff. good parts.