Is is possible to check the timing on a 98 neon DOHC?

Hello forum, I've been having to do some very periodical repairs on my 1998 neon with DOHC. After all that has been done, there has always been one symptom that was very intermittent and slight, which always went away after each engine-related repair/maintenance. Well, its not intermittent anymore, it is constant and not in the least bit slight. I would consider it to be not driveable right now. The symptom is a rough idle. Actually its a very rough idle which shakes the whole car. Until now, I could give it some gas until it got above 2500 rpm and the engine would run smooth. Now it runs rough from idle all the way to 4000 rpm (and probably further). I believe I have a timing problem. I know the timing belt is not broken, however it is possible it is damaged, I just haven't looked at it yet.

I want to know if there is a way to check the timing of my engine before taking the entire front end apart. I'll be doing this myself because I don't have the money to pay for labor.

FYI:
I have done the following tests:
spark test: OK
coil test: OK
fuel injectors: OK
+new spark plugs
+new starter assembly
+new battery
+new crankshaft position sensor
+new camshaft position sensor
+new EGR valve/relay

I believe it is impossible as the PCM controls the timing, and even the voltage regulator for the alternator is controlled within the PCM.

does it hesistate, lack power, or is it more of a vibration.... how's the compression, wires, fuel pressure, fuel quality

Just in case it matters, i have the manual transaxle.
...

I believe it is impossible as the PCM controls the timing, and even the voltage regulator for the alternator is controlled within the PCM.

What about the timing belt relationship between the crankshaft and the camshafts? I fear that the timing belt has slipped, and that is what I want to test/check (sorry, guess I could've been a little more precise in my query). So does the PCM use the crank/cam position sensors to control the injectors and the sparks?

does it hesistate, lack power, or is it more of a vibration.... how's the compression, wires, fuel pressure, fuel quality

It doesn't feel like a lack of power, and its more of a violent shake than hesitation or vibration (at idle it shakes at a relatively slow rate, like two shakes per second). I don't know how to check compression (but i'll look it up in my Chilton's book), wiring harness appears to be good just dirty, fuel pressure is good. If you are talking about octane rating, i just use the standard 87. Is there something that can contaminate the fuel quality?

The only thing I can think of that would contaminate the fuel is water (unless the tank has been opened). I would try dumping a couple of bottles of HEET. Water Out, Dry Gas in the tank, if there is condensation in the fuel these products will homogenize the water and allow it to pass ( I have had this happen to me a couple of times, and the products I listed will help you out, if ti is indeed water).

Pull the spark plugs and tell us if they are still all the same color (the insulator should be a light beige or white) and what the color is. Also tell us if one or more of them are darker or wet. Im wondering if it could be an injector that isnt working? That would result in a plug being darker.
A compression test might be a good idea too.

does it vibrate in the seat. what i'm trying to find out is if it is a misfire or a motor mount issue. Neons are famous for the mounts to go bad