97 Tracer - engine misses but "Check Engine Light" does not come on

I have a 97 Mercury Tracer 2.0 L SOHC. I just replaced the Head Gasket because it was leaking water into the number 2 cyclinder. It had been running very rough and loosing about a gallon of coolant a week lately
(but no visible leaks). I had suspected a head gasket over a year ago, but the engine didn't seem to be running that bad, and a compression showed no loss of compression. I took it to the local Mercury Dealer and they did a coolant pressure test, showing the problem. Anyway they said the head gasket was leaking so I replaced it myself. I also replace the Engine Wiring Harness, because I had noticed that when I minipulated that, it cause the Engine to smooth out or run rough. I also repalced the spark plugs which were due as well as the fuel filter.
So now I have it all back together and even though it runs significantly better than before I replaced the head gasket and wiring harness, the engine is still missing, both at idle and while driving at all speeds. What's interesting is that it does not seem to miss constantly. It will run fine for several minutes, than it starts missing, and then it will go back to running fine and then back to missing. I looked for a vaccum leak, but haven't been able to pinpoint anything yet. The engine check light does not come on, and so I used a EZ Read 2000 thinking it might be burned out. When I run the scan it says MIL off. When I check the data and it shows "No Trouble Codes Available". I called Autoxray and left a message, and technician called back and said that means the same as "No Trouble Codes Found" which is what the instruction manual says I'm supposed to get. She says, the engine check light is not on, and so that's why I get the message I do. However, I kind of wonder whether "No Trouble Codes Available" means what the technician indicated it meant, or something else. You would think they would know, but one thing I learned, in just about every field, there are technicians who don't know what they are talking about. One of the things I find odd, is that when I remove the PCV valve, there is no change in engine performance. Previously removing the PCV valve would cause a huge change in performance, causing the engine to run very rough . . . hmm
For those of you who don't know, this is a Solid State or Distributorless system, and the "Electronic Control Box" which replaces the distributor, was replaced about a year or so ago.
If anyone has any ideas, I'd appreciate it, I really need the help.
Thanks,
Dan
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damox wrote:
damox wrote:

Originally I was sure the problem was due to a vacuum leak. So I looked high and low for such, and even loosened and retightened the intake manifold bolts, after a friend reminded me that the bolts needed to be tightened according to a specific sequence. I admit, I had missed that, because I had not originally seen that in the books I'm using. While retightening those bolts didn't seem to make a huge difference, it did seem to make the engine run somewhat smoother .. . . but still I had the problem.
I wouldn't have guessed it, but it turns out that #4 cylinder has 33% lower compression than cylinders 1 and 2, and about 30% less than #3 cylinder. I suppose that is why the engine is missing, however I am surprised that the "Check Engine Light" doesn't come on. It actually is running pretty good now after I made an adjustment to the #4 injector. For some reason changing the position of the electrical connector going to the Injector for #4 cylinder (sliding it from left to right) , makes the engine run significantly better! I'm not sure why that is, but while it is still running a bit rough, it is now very acceptable until I can either fix the problem, or my daughter can get another car.
Dan
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