Stumble at idle **SOLVED**

[Bleepster]

2011 Silverado 5.3L 116K

went thru the car wash Saturday and afterwards I could feel the engine stumble while stopped at stop lights and while parked in driveway.  I just assumed something got wet.  still have stumble today.  I plan on double checking to make sure plug wires are still properly seated.  I have had one come off before.  I also plan on cleaning MAF.   

is there anything else I can check?  there are no codes or CEL

 

thanks 

[richard wysong]

If the spark plugs have some miles on them I would at least check them.  If your scan tool does live data check the misfire counts to determine which cylinder(s) are the problem. It also could be a vacuum leak

[Bleepster]

i should have mentioned - new plugs, wires and coils within last 3 years.  and good call on vacuum leak - i will investigate

[Bleepster]

SOLVED

 

spark plug wire #4 popped off the plug......... AGAIN.  popped it back on - should be ok

[dna9656]

Maybe a different brand of plugs or plug wires is the fix, plug wires don't just "come off" a plug any more; haven't done that in 30 years. Most plug wires are really tough to get off whether they have been installed for 5 years or 5 minutes....

[Bleepster]

well - ya get what you pay for.  but #4 popped off on my way home.  swapped them out with OEM last night and all is good.

[richard wysong]

Sometimes all it takes is a little moisture in the boot and as it heats up running that turns to steam and pops the wire off the plug. New wires was a wise move

[Bleepster]

these new wires (OEM) are maybe 2" longer than these other junk ones i bought.   these other ones were always a very tight fit

[It's Tim]

Apply to inside of boots:

 

[Bleepster]

YES - I do/did that - with a q-tip