In the past few months, I have developed a miss in my '94 LT1 with 104K miles. It started as an occasional miss and overtime became worse and worse to the point that now it is very hard to drive most of the time but sometimes runs perfectly (not very often). I found that the plug wires were arcing out everywhere and I replaced them and the plugs. The old plugs looked fine. While they are no longer arcing, it hasn't at all solved my problem. I have checked the injectors and found that when you attach the noid light to the injection electrical plugs, you get some strange results. When the car is running and you unplug an injector and plug in the noid light, the engine bogs a little as you would expect but the noid light will not light. Even if you plug the injector back in, it will not return to a normal idle for several seconds or until you idle up the car for a few seconds. If you start with the car engine stopped and attach the noid, it will light up immediately when you start the car and for the most point will pulse as it is suppose to but occasionally will miss some pulses. It seems to me to be the injector drivers in the PCM/ECM. I don't know if any of you have tried to find this part, but it is nearly impossible. It took me nearly 4 hours but I think I have found it through Summit with a new AC Delco PN. What are your comments on this baffling mystery? NOTE: It is not the Opti. Spark is fine.

 

Unplug all 8 Fuel injector clips for testing.

Take your noid light and check each cylinder for an injector pulse.

If their is no injector pulse still on any cylinder, suspect a bad injector driver inside of the ECM.

If their is an injector pulse on all 8 cylinders, then get out your Ohm - DVM multimeter.

Check all 8 injectors for an Ohms test. Should all match one another within 1 ohm.

I believe the resistance spec for your 1994 is 12-14 Ohms.

If you find any bad injectors, they will need to be replaced.

 

I ohmed the injectors. They all ohm out at 14 - 14.1. The injectors themselves seem to be fine. I emailed Jon at FIC. He said that he would gladly test them for me if I sent them to him. Unfortunately, it is my daily driver and I can't be with out the car that long. I also found a shop locally that can send the ECM off to be repaired but it would be gone 10 days. That creates the same problem as above. (daily driver) The injector pulses problem is not constant, it is hit and miss as is the drivability issue. Thanks for the reply.