My 94 sputters at low speed/acceleration only when car is hot. It does not have this issue when the car is cold or been sitting for a few hours. I stared with the usual suspects and changed out the plugs and cables. Previous owner changed the OPTI at 70k. Car now has 133k. Car does not have a check engine lights. Also, car just passed a California Emissions test(smog check). i was thinking maybe faulty o2 sensors but not sure since it did just pass that smog test. Any ideas?