My family owns a 97 Aerostar 3.0 2WD, it's got about 175K miles on it. A few months back there started to be a issue where if it was sitting in park the idle would drop suddenly and then come back up, especially when you first start it, then about 2 weeks ago the van was started and it began shuddering badly, there was no backfiring, but there was definite constant vibration/shuddering, with very little power during acceleration, after taking it to Autozone and having the code reader put on it, it showed a code for the camshaft position sensor and a code p0171. So I removed the camshaft sensor and found the magnet had fallen out, and stripped the vane right off the shafts and polished the top of it in the process. I ordered a Dorman camshaft synchroniser and sensor and installed it per instructions on this site, lining up the crankshaft TDC using the missing tooth in the gear. After that the shuddering wasn't as bad, but still much worse than the day before this occuring, I decided to check the sparkplugs, front driverside was worn down, so I installed new plugs, there is was something odd about how the plugs looked tho, on bank 2 all the bottom electrodes were heavily worn, and the rear one smelled of gas, on bank 2 all the bottom electrodes looked great and not wore down at all, but the middle and rear plugs reaked of gas, while the number 1 plug looked and smelled fine. Well, after doing this, the shaking was still there, mind you there was never any engine noise like the lifters had gone bad or something rattling in the engine. So I remembered a trick to test the sparkplug wires and sprayed some soapy water on them, sure enough I could see them sparking to each other in the dark, so after replacing them as well, this plug fiasco taking about 2 days to complete, I really didn't see any improvement, so now I was very perplexed, I was still getting code p0171, I sprayed around the intake heavily with carb cleaning and didn't notice any RPM increases, so I think I ruled out vacuum leaks, I then took it to a buddy who owns a shop and they quickly ran it thro some tests, cleaned the throttle body, and even tested the o2 sensors, he said the sensors were a little worn but still working and wouldn't be causing this, he said to replace the coil pack and see if that fixes it, and after that check the engine compression which sounds like a major issue. We bought this car used and never replaced the coil pack, and this was the first time we replaced the wires. Does anyone think this could be the coil pack doing all this? And what about the odd condition of the plugs? one bank being heavily worn with one plug smelling of gas and the other not very worn but but two of the plugs reaking of gas? The only other odd thing I noticed was, after driving the van for about 30 miles and going back to check the camshaft synchroniser, it was out of alignment with the crankshaft according to the alignment tool, ie I brought it back to TDC and the tool would no longer fit into the synchroniser housing, I realigned everything but that didn't fix the issue. I'm very perplexed about all this, any advice would be much appreciated!