'97 dodge intrepid, 3.5/24 valve engine, has rough idle, sometimes wants to die, especially in gear ( but runs very smooth at low & highway speeds ). Check engine light on, showed problem with EGR system. Replaced: EGR valve, Intake manifold gaskets, coil, ignition wires and plugs. Ran Sea Foam cleaner thru intake manifold and added it to gas tank.... didn't fix it. Car doesn't smoke, has good power..... any ideas ?

A blinking or flashing check engine light indicate misfiring. I suggest you check the components of your secondary ignition system especially if it worsens when it's damp.

I don't know this specific car. But, if it has one, check your Idle Air Valve. This can cause the engine to stall. If you can hold the gas pedal and the engine will continue to run until you let off the gas, it is likely the IAV. It will not necessarily cause the engine to run rough. That could be a number of things like spark plugs, wires or dirty injectors. It could also be a compression problem. Is the check engine light on?

check for ghost codes, the light does not need to be on to have codes stored. I would also check your vacuum lines as these can have strange impacts on a idle. check you pcv valve to make sure it is working proper

Do the service below.

Engine stalling and rough run issue at low speeds

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control. If this doesn't improve the problem you have mechanical problems in the engine like a low cylinder die to worn rings or leaking valve seats.

Do the following

Here are the most common causes of idle surge, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

that sounds more like idler control valve, but the egr is in close position all the time, opens only when is in gear, and is controled by computer, rpms, etc. Thanks.
P.S. what you can do is to check if is open when the engine is off, is this is the case then you need a new egr. good luck.

EGR valve, Idle speed controller

it sure sounds like you have an EGR problem. This valve controls the flow of unburned exhaust gases and re-routes them too the intake to be re-burned. This valve is usually open at highway or cruise speeds. Not usually open at idle. If this EGR valve is open at idle, you get a rough running for sure just like a mis fire and will smooth out as your speed increases. I would get that checked out and if faulty, replace. Please keep in mind that this part is quite expensive new, but it is electrically controlled. good luck!

Yes, especially at idle on some vehicles, then seems to smooth out a bit at highway speeds.

possibly a bad fuel injector. sometimes when cars are ran completely out of gas, the pump will pull tiny particles out of the tank and will clog the injectors.