[aero246]

I suggest having your injectors cleaned before you do the head if all else fails. Do everything here that is listed from other users and if no satisfaction even after the mystery oil then do you injectors. You can take them out yourself, send them off to be thoroughly cleaned and flow tested. This should cost anywhere from $12 per injector to $25. Search the net and you can find good deal. Just make sure you mark which injector goes with which cylinder so when you re-install there is no problem. Good luck and let us know. I just realized, you may not have actual injectors, you may have a throttle body injection to which my advice would be incorrect.