This article describes how to replace a distributor cap and rotor in most late model 1990’s Chevy eight cylinder vehicles. If your vehicle is displaying some of the following symptoms it may indicate that the distributor cap and/or rotor is faulty.
1. Engine is misfiring
2. Engine is hard to start
3. Engine stumbles
Although these symptoms are a common diagnosis of a bad cap and rotor, they could also indicate other problems as well. Such as bad timing, faulty spark plug wires or bad spark plugs to name a few. Before working on your engine it’s a good idea to place a fender cloth over the area where you will be working. This will prevent your paint from getting scratched.
In most engine compartments the air filter can be removed first to allow easy access of the distributor. To replace the distributor cap and rotor number the spark plug wires 1-8. Marking the wires will save you time and frustration later. If the distributor cap is not numbered 1-8 then label them now. Twist and pull the spark plug wires off of the distributor cap carefully.
Take a Phillips screwdriver and unscrew the distributor cap. Remove the cap. The rotor on these late model Chevy’s will usually have very small bolt type screws holding the rotor on. Unscrew the bolts and remove the rotor and replace it with the new one. The rotor should come with new screws. Do not over tighten these screws or it will strip the threads.
Install the new cap. Plug the wires back in to the correct numbers. Start the engine. Does it run smooth? If it’s clunking then a couple of the wires may be in the wrong place. Check the numbers of the distributor cap and make sure they match the numbers on the spark plug wires. If they match and the engine runs worse than before, you may want to recheck the cap and rotor to make sure they are seated properly.
When working on an engine, it is always a good idea to purchase a repair manual specific to your vehicle. They provide important how to information as well as diagnosis of problems and safety tips.