Chrysler Repair: Neon almost dies at idle, Rpms dropping, plymouth neon expresso, intake manifold gasket

Question
I have a '97 Plymouth Neon Expresso, and I have been experiencing problems when it is at idle. It would periodically die whenever I took my foot off the gas, and the Rpm would drop very suddenly. My husband discovered that the EGR valve was bad, so he replaced it and a cracked hose.

The check engine light is no longer on, however; after a week the car died again when I took my foot off the gas.  He cleaned the throttle with spray cleaner and replaced the air filter, spark plugs, & wires, but the car is still idling strangely.  It has not died again, but the Rpms will periodically drop to the mark between the 1 and 0, and the car runs rougher.  Then it will suddenly stop running as rough and the Rpms settle just below the 1 on the tachometer. It is doing this when in park and stop & go traffic (very nerve-racking.  

He borrowed a DRB  and the only read-out was that cylinder 1 was misfiring about 1/3 of the time.  He cleaned the engine coils, which were gunked-up, but no change. The car is also "bucking" when it hits 15 mph and the Rpms drop from their climb towards 2 almost instantly down to 1.  My husband wants to work on the car himself, but we're unsure of what to check/replace?  

Answer
Hi Rachel,
My thinking is that there is an intermittent problem with the mixture. I am thinking about a crack in a vacuum hose or a leak somewhere around the intake manifold gasket. So I would use the EPA vacuum hose diagram on the underside of the hood to trace and inspect all the vacuum lines. In addition he could try spraying around outside edge of the intake manifold with very short spirts of stater fluid, while the engine is running to listen for any alteration in the idle speed simultaneous to the spirt. I applaud his finding that the egr was faulty as that is a common cause for these symptoms. He might also want to check the PCV valve, or better yet change it.
That is how I would approach that P0301 code. And of course periodically check it with another readout via the DRB.
Please let me know if any of these ideas prove helpful. There are alot of possible reasons for misfire, but because your engine seems to do this intermittently I suspect it is not mechanical, nor ignition related (unless it is too minor a misque to set a code), but rather a mixture issue. He might want to check the resistance of the two coils: primaries should be 0.45 to 0.65 ohms, while the secondary towers should be 7,000 to 15,800 ohms between them.
Roland