I have a 1994 Fleetwood with the LT-1 350 with about 100,000 miles on it. I had the Opti Spark replaced about 18 months ago. The shop I used put one of the aftermarket ones in which after doing further research I found out was a big mistake. Since then they have pit in 3 more luckily at no cost to me. It is now starting to idle a little rough and the exhaust smells like it is a little rich. The check engine light came on and after learning about the diagnostic mode on the car I checked it. Code 00-16, Distributor low resolution pulse not received by ECM, and code 00-43, One or both knock sensors were either open or grounded, were showing. I cleared them out and when the check engine light came on I checked it and found that 43 comes on first and after a couple of days driving it the code 16 shows up. Is 43 causing 16, is 16 causing 43, or do I have 2 different problems. I need to find out before I take it back to the shop for the distributor if that's the problem.