I installed the new injector and it runs better but rough. I installed a new crankshaft position sensor and it starts good. Idles okay and throws a 303 error code.

Considering potential bad new injector I swapped w/# 1. Misfires on 1 & 3. Reset codes then only misfire on 3.

Installed new fuel filter...no change. Metered wires between ecm, pcm and spark plug coils and injectors. All read the same. I visually observed the intensity of spark plug flash and they appear the same.

I checked compression and read 148-153 on all cylinders...good I think?

I opened up the ECM and resoldered all transisters including 6 in line which seemed maybe to be drivers for the plug coils or injectors....multiple errors including throttle position sensor error. Couldn't erase them. I pulled the battery and let it sit for a couple hours. Started it up and got 303 code...at idle. Took it for a spin...it ran a little rough until I stepped on it a bit....ran rough then rougher...happy to get home. Codes 300, 304, 301, 303.

Again I swapped coils, wires and plugs between 1 & 3. At idle, 303...took it for a spin...same as above.

I left it sit for a couple weeks hoping it would fix itself...that didn't happen!

Today, 2/8/14 14:00 C.S.T. fired it up (it started easily even at 0 degree temp and not running for 2 weeks) and let it warm up 5 min. 303 error. Took it for a spin...no power and ran a bit rough. Stepped on it a bit and it ran rougher then rougher...I was happy to get home. Codes are 300, 304, 301, 303(total 8 codes).

Questions:
1. Knowing firing order to be 1-4-3-6-2-5, if there is a broken tooth on the ring gear between 4 & 3 would this cause a 303 only?...misfire on all cylinders always?...missfire on all until # 1 fires again?

2. If the timing chain was faulty or slipped, wouldn't it misfire always on all cylinders whether idling or driving?

3. I haven't replaced coils and plug wires because swapping hasn't seemed to matter. Could I be missing something there that would cause such consistent symtoms?

4. Boy, I could use some more good advice and a stroke of luck.

Thanks for all your help everyone.

Gerry