I recently had lots of work done on my 1993 Pontiac Firebird Formy at my job since I get a 75% labor rate. I bought lots of nice new shiny parts like a full MSD ignition kit and a nice new stage 3 exedy clutch kit, etc. I go pick it up from dealership and its running worse than before! I pulled codes and I got code 26. Quad driver fault, maybe purge valve/solenoid? Either way, I took it back in for them to fix. They come back and tell me lots of ****, but the main things were Distributor (which literally just got installed), EGR valve, and IAT. All of these can make the car run like **** but im definitely not about to buy a brand new distributor AGAIN because they fucked up the first time. IAT and egr purge valve i can understand. What do yall think

Notes from technician:
Diagnostic: code 16, 23, and 26 present. dtc 16 performed test . 4.7v at terminal a. jumper harness ohms out. suspect faulty distributor. code 23 manifold air temp. ppt ol at sensor. recommend replacement. code 26 quad driver ckt. ground terminal b egr solenoid and air bypass click. purge solenoid does not. as per ppt recommend replacement

TL;DR: Car stumbles and runs rough/only codes thrown is code 26 but tech states that there is also a distributor and IAT issue too

 

MSD Opti sparks have had a bad reputation for having poor quality. Some have gone south shortly after install.

 

This, OP. IDK why MSD continued to make the Opti with all the failures they had. Do you still have the original opti that came out? If your willing to tackle it, id throw it back in to see what happens.