I have a 96 3800 Series II and read here that theres a date code stamped on top of the plastic upper intake. All i see is a bunch circles&numbers. How do i decipher these into a date?? Thank you ALL for any help..

Take a close look at each circle. One will have 1 to 12 with an arrow pointing to one number. That'* the month. Another will have part or all of 1-30(31) that'* the day. And the third should be 0X to 0X being the year.

Sir; You Da Man!! According to my date code its - 1-25-02 . So am i correct in thinking its been replaced? Again THANK YOU for your help.

Yes. Whether or not it was replaced with a revised intake that doesn't have the EGR/Coolant leak problem is a different story.

No coolant leak, just slight rough idle. Been doing it for about 5 years ( spare car barely driven ). Have done all the normal stuff= plugs wires ect. Can the egr port leak vaccum on the inside?? Thanks.

Here'* the problem in a summary.

The EGR stovepipe comin in through the upper intake manifold touches the plastic walls of the upper intake manifold around it. Adjacent to that EGR port are the throttle body coolant passages. The heat cause the plastic to become brittle and crack over time, which can potentially cause a severe coolant leak. Its a ticking time bomb.

The revised upper intake manifold includes a revised stovepipe which has a smaller opening, allowing a pocket of air around the pipe itself so that it doesn't directly heat up the plastic and cause it warp, crack, etc.

Try cleaning your mass air flow sensor. Does the idle bounce around in the revs, or is there just a vibration in the car? A broken engine mount can cause excessive vibration to be transferred to the chassis instead of bein absorbed by the mount.

EGR ports don't leak vacuum. The purpose of EGR is to allow exhaust gasses to flow back into your intake. The purpose of this is to mix air coming through the throttle body with exhaust gasses, which cannot be combusted as fuel. This artificially lowers the effective displacement of your engine, causing your fuel economy to decrease, along with depositing carbon on the intake runners over time. The fact that it is exhaust gas is what causes that stovepipe to get so hot and cause damage long term. You should be able to confirm if you have the revised stovepipe by removing your throttle body and shining a flashlight in there.

The idle bounces a little 450-600 rpm, mainly a vibration in gear. 2 weeks ago i replaced all the motor mounts & trans. mounts (fun) helped a little but still vibrating some. Is the dorman intake a revised one?? Also before i replace it should i try seafoaming first thru the brake booster hose?? Thanks

I've seen revised and non-revised both have issues. The revised are definately stronger and less prone to issues.

Good to know. My revision when working on such intakes is to plug up the coolant throttle body passages. Problem solved.

Me too...