VR V6 missing at idle

[-=$natch=-]

Morning guys & girls,

Since I got the car about 6 months ago, I've noticed that when it's at idle it slightly misses a beat every 30 seconds or so. It's only a very brief miss of about 1 second and doesn't even register on the odometer and doesn't really effect anything, but if it's something common that can be easily fixed I may as well do it. Now it only does when idling in Park or If I'm stopped in Drive...I'm guessing it only does it at idle as I don't notice it any other time.

Other than the small miss, it generally idles very smooth for a buick v6. Also the engine has done over 435k and is a little rattly inside but generally runs well.

Anyone have an idea of what would cause the missing?

TIA

[c0rboVR]

mine does that when its cold. but once it gets running its all sweet.
when its first started my idle fluxuates alot... but im sure thts normal for an old car. mines done 310000 ks

[lil_mickey]

As a quick guess I would suggest to both of you to check the o2 sensor

[The1]

have you cleaned the throttle body? is it only cold or hot or anytime? how old are the plugs and leads? Fuel filter been changed?

[Brett_jjj]

Oxygen sensors wont cause a miss,especially when the engine is cold,they arent even used until the engines starting to warm up to operating temp.As mentioned above,plugs ,leads,filters,and run a bottle of injector cleaner through the fuel tank.

[-=$natch=-]

In the past 3 months I have replaced the plugs, oil & filter, fuel filter. I have had the throttle body off and cleaned it up and it looks like new, have run 2 bottles of injector cleaner through it...etc

Only thing I haven't changed is the leads as they aren't very old...but I guess it wouldn't hurt to get some new ones for the price.

It does it when it's cold and hot, doesn't really effect anything, just annoys me that it does it.

[alex2_s]

if its only a small miss every occasionally its probably not worth worring about if the general maintenance items are up to scratch (filters etc as you've just said they are).... especially given the km's of the engine it could be anything like something dodgy in the valve gear, vacuum leak, exhaust leak etc....

leads and coils can also be checked with a multimeter for their resistance.