Re: having issues
If it was valve timing or ignition timing, all cylinders run the same- bad. It sounds like its running on 3 or 4 cylinders. Checked crossed wires, unplugged injectors, stuck/plugged up injectors. But to rule out mechanical issues without doing an actual compression test, first disable the ignition coil and crank the motor. Listen to the motor. You should hear even pulses while cranking. If you don't know what that sounds like disable a good running motors coil and listen to what it sounds like. The starter strains agaist compression, if there is a valve too tight it will hang open and have no compression. The starter will breeze right past that cylinder as if the spark plug was out. May sound basic but sometimes that is where you have to start. Try this before tearing stuff apart. Good luck