This article gives detailed instructions on replacing the spark plugs and ignition coil in a Chevy Silverado 4.3L GM800 vehicle. Even though we used a 2006 Chevy Silverado to perform this repair, this article can be applied to any 1999-2006 Chevy or GMC 1500 pickup with the Vortec 4.3L V6 engine with minor modifications to the repair steps.
A Chevy Silverado V6 tune up is an inexpensive way to return factory fresh performance to your 4.3L engine.
One of the more satisfying repairs home mechanics can do on their Chevy Silverado or GMC Sierra is replacing the spark plugs and ignition coil. Not only does it save a bunch of money by avoiding the dealership or local repair shop, it also gives great pleasure every time you step on the accelerator and enjoy that renewed performance to the 4.3L V6 engine.
A Chevy Silverado V6 tune up includes replacing the spark plugs, spark plug wires and ignition coil. The 4.3L Vortec engine used in the Chevy Silverado and GMC Sierra uses only one ignition coil – its job is to convert 12v battery power into a high voltage charge that is distributed to the six spark plugs. The spark plugs use this charge to ignite the compressed fuel air mixture in the cylinders, creating the engine power needed to drive the vehicle.
Age and the brutal engine operating conditions take their toll on plugs and coils slowly causing them to lose their efficiency. As the plugs and coils start to wear the engine can become sluggish during acceleration, or exhibit shaking and shuttering due to cylinder misfires. Worn out spark plugs and ignition coils can also greatly affect the vehicle’s fuel economy. The ASE has reported that fatigued spark plugs can decrease fuel economy by up to 30%. Failing spark plugs and coils can also cause vehicle stalls, rough idling and in extreme cases a complete engine “no start”.
Installing aftermarket ignition coils
The factory ignition coil in the Chevy 4.3L V6 is actually permanently riveted to the mounting bracket that it shares with the ignition module. Aftermarket ignition coils for the 4.3L V6 do not include the mounting bracket. In order to install a new ignition coil while performing a Chevy Silverado V6 tune up you will have to remove the mounting bracket and ignition module – if it is an original factory coil you are replacing, this will require drilling out the rivets that hold the bracket together. Do not be intimidated by this step. It is extremely easy and only takes a few minutes with the aid of a drill and a 3/16″ bit. The new aftermarket coil can be attached to the old bracket with a couple of M4 70mm bolts (see our repair steps below).
The good news is a Chevy Silverado V6 tune up is a relatively easy repair for the home mechanic and does not require any special tools. It can be done in about 1-2 hours and will save you a ton of money by avoiding the Chevy dealership or local repair shop. We provide detailed step by step instructions below along with a complete parts and tools list.
1. Spark plugs (required) – One of the biggest mistakes home mechanics make is trying to save a few bucks by using cheap aftermarket spark plugs in their Chevy/GMC engines. Cheap “generic” plugs have a much shorter life span than OEM quality ones. We give you a couple of great choices below for your 4.3L Vortec engine based on your brand preference and budget.
Spark plug – ACDelco 41-993
Spark plug – NGK 7164
2. Igntion coil (required) – Like the plugs, it is important to use a high quality ignition coil in your 4.3L Vortec engine.
Ignition coil – ACDelco D577
Igntion coil – NGK 48604
3. Spark plug wires (required) – One of the most overlooked parts in a 4.3L engine tune up are the spark plug wires. Spark plug wires have a limited lifespan like the plugs and coil and must be replaced. We give you a couple of high quality choices below.
Spark plug wireset – ACDelco 9746MM
Spark plug wireset – Duralast D801291
4. Air filter (optional) – Now is a great time to replace the air filter in your engine. Keep you 4.3L V6 breathing easy with a fresh air filter element today.
Air filter – AC Delco A3181C
Spark plug gap tool
10mm socket wrench
Spark plug socket 5/8″
Torque wrench- low range
Torque wrench – medium range
Drill – cordless
3/16″ drill bit
CRC Electronic Cleaner
Removing the ignition coil when performing a Chevy Silverado V6 tune up requires loosening the throttle cable brackets on the front of the throttle body. You will not be able to remove the two coil bracket mounting bolts unless the throttle body brackets are removed.
- Use an 8mm wrench to disconnect the negative battery cable from its terminal. Always disconnect the vehicle’s battery before performing any repairs on the engine’s electrical system to prevent catastrophic damage to sensitive electronics.
- The ignition coil is located on the top right side of the engine underneath the intake air duct assembly.
- Start by disconnecting the mass air flow (MAF) sensor by raising its plastic release then depressing the locking tab. Pull the plug free from the MAF sensor.
- Loosen the hose clamps on each end of the intake air duct. Remove the duct from the vehicle.
- Remove the plastic nut from the resonator. Pull the resonator loose from the throttle body and remove from the vehicle.
- Locate the coil on the top right side of the engine next to the throttle body.
- Unplug the coil’s two electrical connections.
- Unplug the ignition module attached to the coil bracket.
- Next, the left throttle cable bracket must be removed. Use a 10mm socket wrench to remove the two nuts securing the bracket to the throttle body as shown below. Gently push the left throttle cable bracket out of the way.
- Next, the right throttle cable bracket must be removed. Use a 10mm socket wrench to remove the bolt securing the bracket to the throttle body.
- Next remove the two 10mm nuts securing the bracket to the intake manifold. The right throttle cable bracket is now loose…carefully stow it out of the work area.
- The ignition coil can now be easily removed from the engine. Using a 10mm socket wrench, remove the two bolts securing the ignition coil to the intake manifold.
- Remove the ignition coil from the vehicle.
As previously discussed, if you are removing a factory ignition coil from the vehicle then it is most likely still riveted to its mounting bracket with the ignition module. In order to separate the coil from the bracket, the rivets will have to be drilled out and the bracket disassembled. This is a very easy procedure that only takes a few minutes…so don’t let it discourage you from proceeding with the repair.
- OE “factory” coils are riveted to their mounting brackets along with the ignition module. In order to install an aftermarket coil, the rivets will need to be drilled out.
- Place the old coil bracket in a vice with the rear bracket facing up (coil facing down) as shown below. Drill out the rear of the rivets with a 3/16″ bit.
- With the two rivets drilled out, remove the rear mounting bracket.
- Flip the coil over and drill out the front of the rivets.
- The old coil is now free of the mounting brackets.
- Install a new coil to the mounting brackets using two M4 x 70mm machine bolts and washers as shown below. The bolts are readily available from any home improvement store.
- Install the coil bracket back onto the engine. Torque the two mounting bolts to 10 Nm (7 ft-lb).
- Reinstall the right and left throttle cable brackets and torque the nuts and bolt to 10 Nm (7 ft-lb).
- Reconnect the ignition coil and ignition module connections. It is good practice to liberally spray them with CRC Electronics cleaner before connecting them.
Replacing the spark plugs and wires on your Chevy Silverado or GMC Sierra with the 4.3L V6 is a relatively straightforward procedure. One thing to take into consideration is that you will be spending a lot of time inside and on top of the engine…especially when replacing the wires. The plug distributor is located at the back of the engine and you will literally have to get inside the engine compartment to access it. We strongly suggest using a good sturdy stool or small ladder to assist in the procedure to avoid slipping and hurting yourself. Also, make sure the engine has completely cooled before starting this repair to avoid burning your hands.
- Starting on the right side of the engine, locate the three spark plug wires and their clips.
- Grasp the first spark plug wire cap and pull it free from the spark plug. If it is stuck, try rotating it back and forth until it releases its grip. NEVER try and pull the cap loose by the wire (especially if you are not replacing the spark plug wires during this repair) – you will literally pull the wire right out of the plug.
- Using a 5/8″ spark plug socket, remove the spark plug from the engine. You can see our old plugs were well “burnt” and probably the main contributor to our rough running engine.
- Check and adjust the spark plug gap with a gapping tool like the one in our tool list. The correct gap for the 1998-2006 4.3L V6 engine is 1.5mm (.06 in). Spark plugs rarely come with the correct gap already set…you must adjust it with a gapping tool to get the maximum performance and fuel economy out of your engine.
- Spread a small amount of anti-seize lubricant on the spark plug threads. This will make it easy to remove the plugs during the next tune up.
- Install the new spark plugs and torque them to 15 Nm (11 ft-lb).
- Finish replacing the other five spark plugs.
The spark plug wire kit for the 4.3L V6 engine comes with seven wires; one for each spark plug and a seventh one that connects the ignition coil to the distributor cap. Replacing the spark wires can be a little challenging since the distributor they are connected to is at the rear of the engine. ALWAYS pay close attention to which spark plug wire you are replacing to avoid mixing them up during installation. We strongly suggest using a Sharpie marker to label them as you install them to keep them in the correct order.
- Use a very small flat blade screwdriver to release the spark plug wire clips that anchor the spark plug wires to the engine block. These clips can be particularly nasty to release…take your time and use patience or you will end up breaking them.
- Follow the spark plug wire you are replacing to the distributor. It is located on the back of the engine.
- Unsnap any wire clips located along the way.
- Continue to follow the spark plug wire to where it is plugged into the distributor. Grasp the wire and pull it free. If it is stuck, use a flat blade screwdriver to try and pry it off of the distributor as show below.
- Remove the old spark plug wire from the vehicle.
- Match the spark plug wire up with a new one. Make sure they are the same approximate length and have the same style plugs. Apply a small amount of dielectric grease to both of the plugs…this will keep the plugs from seizing to the distributor/spark plug and make them easy to remove for the next tune up.
- Install one end of the new spark plug wire back onto the distributor. Make sure to apply pressure until you feel it snap on.
- Install the other end of the wire to the spark plug. Once again make sure the plug snaps firmly into place.
- When you have finished replacing the six spark plug wires, move to the ignition coil wire. It runs from the ignition coil to the bottom right side of the distributor. It can be easily removed by following the wire with your hand then pulling it free from the distributor cap. Install a new wire making sure it clicks into place on both the distributor cap and the ignition coil.
- Replace all of the spark plug wires using the steps above and reinstall the spark plug clips.
- Reconnect the battery’s negative terminal.
- Start the vehicle and make sure it is running smoothly before starting the final reassembly.
Final reassembly is simply Section 1 steps 2-5 in reverse. Pay careful attention when reassembling the intake air system…if any hose clamps are loose or if the resonator is not firmly in place you can experience vacuum leaks which can play havoc with performance and trigger the check engine light in the instrument cluster. Also double check to make sure the MAF sensor wire is properly connected. We suggest spaying it with some CRC Electronics Cleaner before plugging it back in.