First of all since this is my first official post, I've been a lurker for years. Got into the 3.8 with a 98 Mustang I owned and was looking into a SC engine swap. That Idea passed when I got a steal on a twilight blue 94 SC 5spd. But now onto business, when I bought the car it had a bad alt. I did a 3g 135amp swap; and I have had problems. CEL is lit almost constantly, occasionally (usually when it is cold outside) it will stay off for 3-5 minutes and run completely normal. I have ran it for codes, and the ones that come up are:327,137,173,412,and 538. Now I'm almost certain that my EDIS is bad, I have was seems to be a late ignition problem "occasionally" it has almost no consistency to any driving conditions, except it seems to be more common right about the time it gets up to temperature. This timing problem causes the car to lurch and jerk, this is my biggest concern. As far as I know the Hg have never been done on this car and its at 162k and I feel like if it happens much under boost it could catastrophically have a head gasket fail. I do plan on doing them(With a 3 layer MLS and a full set of ARP studs) but its a HUGE ~~~~ on these because of how everything is so tight. (I had to remove two of my spark plugs from underneath!). Ah, before I forget every once in a blue moon it will idle very rough, almost like I have a lopey cam, as well as die or try to die unless I bump the pedal lightly. Unfortunately I dont believe I am close enough to any other SC owners so I can try someone else EDIS, its quite an expensive module at over 140 new. A little tough to drop that kind of money on something that may or may not fix a problem. I apologize for the long windedness of this post but it is a hard problem to try to explain.