Q: Greg, I have a 1994 Camaro Z28, and it starting running very poorly. I have checked all the plugs and wires, and it is missing badly but everything seems to be OK. I want to keep this car as I feel it will be a classic one day, and it only has 28,000 miles on it. Could it be an electrical short, camshaft or other ignition type problem? Please help. Michael, email from Washington.
A: Michael, I can tell you what it most likely is as I had the same problem with my 94 Trans-Am a while back, and my car has only 14,000 miles on it. The 1993-94 Camaro Z28 and Firebird Trans-Am models, both powered by identical LT1 Corvette style V8 350 engines, suffer from what is called a "non-vented Opti", which translates into the optical spark GM distributor, located near the water pump area. These units cannot dry out moisture if it gets in there, thus they are called "non-vented." My Trans-Am started acting up after I drove in a four-hour rain storm one day, and the Opti got wet somehow and that was it. It could have also been the water pump, too, leaking just a tad of fluid into the Opti.
The 1995 and up powered LT1 models had an improved "vented" Opti, which, sadly, is not interchangeable with our engines unless you change several other items, including the cam. So, I put in a new, non-vented Opti, and it's been flawless ever since. I also changed the water pump to an electric steel billet CSR unit that pumps 37 gallons per minute (they cost about $165-175). I also put in a Hypertech 160-degree thermostat, as our models have a tendency to run hot in stop and go driving. I've had zero problems ever since, and the car's cooling abilities have increased greatly.
It sure sounds like the Opti to me, and if you move quickly you'll find them on eBay brand new for $250 to $320, which is cheaper than I paid. Good luck, and I do feel our cars will appreciate in value as the years go by.