Need some help

[fixkick]

Thanks !

Okay
SO - the BECK 1430688 thermostat I ordered will work for BOTH the 1mm and 4mm lip models, correct?
To determine which GASKET I use with this thermostat, I should measure the lip - if 4mm lip, I will use the rubber O-RING. If 1mm lip, I will use the paper gasket.
 (I ordered both gasket and o-ring from rock auto). 

So your explanation of why the CAT is necessary for the EGR to work properly might explain why the car idles rough. Hopefully the CAT installation will help this issue. 

Thanks for the help Kick!

yes the best ones come with both gaskets,
the EGR dead does not cause the engine ever to do any funny things, cat dead /missing or rodded out   means EGR is dead and fully closed, if is close there are no EGR bad effects possible.
4mm lip must have huge rubber gasket
the 1mm lip can never fit the 5mm rubber ringed gasket.
the 1mm paper gasket is useless on the 4mm pip and allows the STAT to float wildly and horrible effects see my ice berg page. on that.

The eGR working  only does1 thing and 1 thing only, lowers NOX gasses (toxic) (smog reason)
Ok 2 more, it lowers combustion chamber temps and valves exh last longer, and no more pinging if it did ping.

on a normal car with good cat, the EGR issue (old EGR main valve there) is it sticks open as you roll to a stop and engine stalls or runs at 400 RPM and shakes like wet dog.
on your car it never ever opens the EGR so is offline,. and engine runs great, spark good fueling right.

says fits ( I can not speak for any 3rd party maker )

http://www.beckcatalog.com/partdetail.as...THERMOSTAT