Will cleaning the EGR solve a rough idle on a 2005?

[garydee]

I just picked up a 2005 Astor with about 114K on it. It seems to be a nice truck with just a few problems that I will "handy-man" myself.

This engine starts with a "tap" of the key, but here's my question;

At idle, it seems to be smooth but rough - a constant RPM but it's almost like you can feel each cylinder fire - enough that it makes things rattle inside and the steering-wheel visibly vibrate.

Besides this, the engine seems to run smooth at RPM and has decent power. I just changed the fuel filter & air cleaner. Vacuum actuated A/C controls seem to work quickly so I will discount a major vacuum leak. There is NO smell of gas and NO service engine light.

Never owning a Chevy V-6, is this the normal idle of these engines? It does seem just a bit smoother when started cold.

I look toward you and your great wisdom; any ideas?? Could this be a dirty EGR? What ya think? - garydee

[ericn1300]

the egr either works or it doesnt and throws a trouble code, a stuck or dirty PCV valve would be a more likely route. under $2, not even worth cleaning.

[boatbuster]

you mention that you replaced air and fuel filter - did you have a look at plugs, wiring, cap and rotor. this could help your issue if they are getting worn! a word of advice, if you need to replace your plugs think of having it done, some are hard to reach.

[garydee]

Well, I just picked up plugs, cap and rotor (cap and rotor are a bit worn). I'm also going to clean the throttle body and check the egr. Lets see what happens.

[vivaleastro]

be careful with the plug wire routing, especially the coil wire. make sure the coil wire will not contact the underside of the engine cover - if it does, it will short into the aluminum shielding

[garydee]

OK - changed the cap and rotor. I could not identify where the EGR - no luck there.

Here's one thing I noticed, when its first started when cold, idles real smooth. Its only after a couple minutes when the heat builds up you can feel it, almost like its idling at too low an RPM.

[mbmcgin1]

I have tried to find the answer to this question myself, and everything i try never realy seems to make a difference. The rough idle is actually a characteristic of the 4.3 v6's, it idles rough because of the rpm, which is different between vehicles, ours just happen to be a few. In 1993 GM put a balancer bar in the 4.3's to try to fix this problem at low rpm's. The bar is a counter-weighted iron bar that rotates inside the engine right under the intake, (you cant see it by looking at the engine) the catch is that the bar either only works to a certain rpm, or is out of adjustment. My suspision is that there could be a problem with the clutch, but since it doesn't slip, I'm not bothering it!

[brcidd]

I suspect your motor mounts are worn out--mine did this- terrible vibrations eventually-- to test I put a floor jack under the oil pan-with a 2x4 so as not to deform the oil pan-- gently increase the lift- see if vibration at idle changes- the motor mounts are probably touching metal to metal- the rubber area gets deformed to the point the engine actually sits on the frame- and transfers that vibration right into the van....