99 Ford Windstar random stalling/running okay

We have 99 Windstar 3.8L that is perplexing me. It sounds like it misses at idle speed and throughout the driving range. We changed the spark plugs it ran great for a little trip around the countryside, about 18 miles. Then the next morning when I tried to start it was back to missing and stalling at idle speed - erratic idle. The vacuum lines seem to be okay - no hissing sounds when I put a stethoscope to them. We changed the fuel filter, PCV valve, Mass Air Flow sensor (MAF), Throttle Position Sensor (TPS) and it still stalls so bad we can't get out of the driveway to have a Code Reader put on it. After installing the new TPS this afternoon it smells gassy like it's flooding. Could it be a the Fuel Pressure Regulater? The Idle Air Control Valve? Help Please?!:banghead:

You may want to read thru this forum response. It deals with making sure the spark plugs are double platinum, and spark plug wires are good. The coil was the issue, and this may be worth replacing to solve your missing engine problem.

http://www.automotiveforums.com/vbulletin/showthread.php?t=968552&highlight=bad+coil

You can give a good clean to the IAC with throttle body cleaner just to ve sure, but it looks like your problem is either bad wires or the coil pack as grog11 said. It is known to crack at the back and short to ground. Inspect it and replace if needed.

Oscar

I cleaned the IAC today. It wasn't that dirty and the pintil/spring assembly moved freely about 1/4". It didn't solve the problem. In addition to the other symptoms I mentioned in my original post it also bucks and pops when you rev it up. I was reading on here where someone replaced the coil pack and it solved the problem. Ths coil is hard to get to. Someone told me I had to remove the shield between th ewindshield and the hood. Is that true? The idle is rough when you start it and it's been cold and damp the past few days and the problem seems worse. Once it warmed up a bit it seemed to idle more smooth, then it started that erratic idling again. Any suggestions?

The coil pack is much easier to get to if you remove the plastic windshield cowl. its not a bad job really,takes about 15 minutes being careful. There are nuts holding the wiper arms under the shaft covers that need removal 1st, lift off the wiper arms, and then the push pin screws you will see on the front of the cowling by the weatherstrip and on each fender side, lift the top cowling straight up, you will see some plastic snap down adapters under the cowl after you lift it up. You will then see the lower cowling, that has the wiper arm motor attached under it,same thing, unplug the wire connector to that, and lift cowling off after taking the screws out. Now you have easy access to the back wires, plugs, and the coil pack, You will see the screws that hold the coil down. You will maybe want to mark each plug wire with numbered masking tape and write it down before removing the spark plug wires from the coil, they are easy to mix up there when putting them back on.You may want to change the back spark plug wires while it easy to see in the back also.