My 92 940, with Rex/Regina, has been having a rough running/low speed miss problem for a while. It would start up normally, but acted like it was going to stall if revved or put in gear in the first 10-30 seconds after starting, the time period seeming to be somewhat temperature related (colder=longer) In the process of trying to remedy this, I have done the following: Checked plugs (NGK BP6ES) which have about 5K on them, and looked normal; cleaned out the inside of the cap, which was a little oily, but no worse than many others I've seen; replaced the plug wires with a good used set, one of the old ones having been chewed by a squirrel; checked the cam timing, as the symptoms were much like a previous incident, where the belt had jumped a couple of teeth--no power/sputtering at low speed, in drive, normal anywhere above 1500-1800 RPM--found the timing correct, but in the process discovered a separated crankshaft pulley, which I replaced; cleaned the inside of the throttle assembly, which wasn't particularly bad; found and repaired a crack in the hard plastic vacuum line to the manifold pressure sensor; cleaned various fuel and ignition system grounds; replaced the fuel pressure regulator with a good used one; likewise with the radio suppression relay and crankshaft position sensor, all to no effect.

Today, the problem suddenly became a lot worse---the car lost all power going up a hill. It would idle, and rev fairly normally in neutral, but sputter and stall when put in gear. After considerable abuse (several 4000+ RPM neutral drops) I was able to make it to the top of the hill, found it would keep moving on level ground if held in low gear and kept above 3000 RPM, and was able to make it back home. Since then, I have checked both the fuel injection and ignition systems for codes, and found none (both showed 1-1-1, checked them twice) and tested the resistance of the coil, which seemed to be OK, as well as cleaning the spring contacts where the coil mounts to the coil pack, which didn't do anything to fix the problem.

My question is, is there anything else I should check before going ahead and replacing the (expensive) coil pack? I have not checked the fuel pressure, as I have no means of doing so, but it doesn't seem to be acting like a fuel problem---it feels more like the timing is off, or not advancing. If it were a mechanical distributor with centrifugal advance, I would suspect that the weights were sticking or hanging up, as it will idle (in neutral) more or less normally, and run at medium and high engine speeds, but nothing in between. If the fuel pump or its relay were the problem, I would expect the problem to be either unrelated to engine speed, or to get worse as the RPMs increased.

Any thoughts would be much appreciated. Thanks in advance