Originally Posted by JanGeo
Faulty injectors will result in some change in the spark plug ash buildup so by checking your spark plugs you may find the bad cylinders and thus the bad injectors. Other than that you have to see how much fuel they spray when activated in CC per minute and actually measure each injectors spray volume.
granted the mechanic put them back in where they came from
since it sounds like ye olden car and you dont have money, i would try a can of "miracle" (what i liek to call Sea Foam) dumped in the gastank.
i also like to let the engien suck some up thru a vaccum line and let it clean the top end and cylinders.