My 1983 245DL has been hesitating under load. It will drive fine on at normal throttle on flat roads but if you press the pedal to the floor it will hesitate and miss, shaking the whole car. This hesitation is very troublesome on steep hills where you need more throttle. I replaced the cap, rotor, coil wire & coil. The plugs and wires only have 10,000 miles on them. The in tank pump is working. I have checked all connections at the ICU and the 3 pin connector on the distributor. Could this be a bad fuel injector or is there something else I should look at first.