*** New info here in Post #21: http://www.insightcentral.net/forums/showthread.php?t=20996
We have read about the "jerky Jerky" problem not going away with simply cleaning EGR plate passages or with new EGR valve, and this obscure passage being clogged may be the reason. Thanks Scott for posting and explaining! ***
Mods - if appropriate, and would help future readers/search effort, consider merging these threads.
The ghost in the machine. Hope you can solve it but I have seen so many who have wholesale replaced the entire exhaust and every other conceivable part and still have a stoned car. I've lived with the P0420 for years. Good luck!:-|
Ordered the parts and finally had some time to do the EGR plate removal and cleaning.
All I can say is "WOW" what a gummed up mess, I'm surprised it even ran!
It took me about 2 hours total to remove / clean and replace with all new gaskets.
The biggest issue I had was replacing the crazy little hose clamp underneath the intake manifold.
I was hoping that it would stop the "bucking" and has most of it.
But, now I'm thinking that the "EGR" needs replaced to completely eliminate the issue as it too has over 200,000 miles on the stock valve.
I was doing a search and found this EGR valve for $50.00 bucks off of e-bay and was wondering if anyone has used or is using it? Standard T Series EGV658T EGR Valve | eBay