Rough Idle

[CapitalMark]

I have a 2002 Yukon 5.3. I just changed spark plugs and wires and now it seems like the engine has a bit of a rough idle. I set the ACDELCO plugs at .060 per the manufacturers recommendation. Heard conflicting info between .040 and .060. I changed the PCV also and it was the dirtiest PCV I've ever seen. Anyway, just hoping you all might have some ideas. Full disclosure it does have 304,000 miles on the engine. Should I just be lucky it runs?

 

[OR VietVet]

Clean the throttle bore and the MAF sensor

 

[CapitalMark]

Awesome! I'll try that, thank you!

 

[OR VietVet]

Use carb cleaner for the throttle bore. Clean where the throttle plate closes and at the plate edges. Do not open it to wide open throttle. Have someone hold the gas pedal down while you do it but again do not go to WOT. Get MAF cleaner at the parts store and follow directions. It will likely idle high for a day or two, depending on your driving habits, while it relearns.