Here's the sequence of events:

Last Monday: drove the car ('98 V-6) 3 hours away to a small country town to buy a boat motor. Was in town for 15 minutes, purchased motor and began the 3 hour journey back. I immediately noticed a slight misfire in the car engine.

Tuesday: ran errands around town and misfire was 10 times worse

Wednesday: brought car to IdiotZone for computer diagnostic. Idiot employee tells me P0300- engine misfire. Really? I already know that. Then Idiot informs me of second code P0306- misfire on cylinder 6. Thank you, that's a little more helpful.

Thursday: returned to IdiotZone and purchased plugs and wires. Got home and realized the dilemma of changing plugs and wires in these cars. Easiest waterpump change in history but a basic tune-up is a b****. Thank you, Chevy.

Called local mechanics and they said bring it in on Monday. Borrowed my aunt's TP Cruiser for the weekend and let the camaro sit.

Now here's the kicker: Monday morning, after sitting since Thursday, I cranked on the engine and all 6 cylinders were in perfect harmony. I even passed up the mechanic shop and did a lap on the freeway.

After freeway, misfire kicked back in. Right when the choke is leveling out and the thermostat is opening up. Sooooo, while yes my plugs and coils are original and due for a change, I'm wondering if the immediate problem is something else.

What leveled back out, or relaxed so to speak, while the car was sitting for 4 days?

I need one genius to tell me WTF this means.

By the way, this is the second time the car has given me trouble after spending money on the boat. Don't ever let your wife catch you spoiling your mistress...

 

could be the wife caught you cheating and now shes messing with your car lol... could be a loose connection the fact that sitting "fixed" it is slightly confusing... id still change the plugs and wires maybe the coils too and see if the problem is still there

 

What was your weather like? It was a rainy, damp, and sometimes foggy weekend here. If you have bad plug wires (cracked or leaking electrically), moisture in the air (water is a conductor) can make a misfire worse, or can create a misfire that wasn't there before. See what happens, or doesn't, after new plugs and wires.

 

No one can answer your question. The miss fire code is very generic. It can be due to high voltage, low voltage or circuit simply did not fire. The only way you can figure out exactly what is going on is a trained person and engine analyzer with a Scope. This combination of person and machine is expensive. It is always cheaper to do all the required routine maintenance before you go this route since it needs done anyway. I am not one to throw parts at a problem but making sure all routine maintenance is done before spending a min $150 for diagnoses just makes sense.

Your spark is like water under pressure, it is always looking for a place to escape. A cracked plug can change due to heat of vibration same with a wire. Moisture can be an issue as with cracked/worn parts Camaro 69 said. Even too much moisture in the cylindered itself (AKA a blown head gasket) can cause a “Misfire”, low compression or running rich also.

The most common issue with these cars and misfires are plugs and wires not being maintained they cause the coils to fire at the max voltage all the time and they get to the point they can no longer fire the plugs. Once the plugs and wires are replaced everything is fine (assuming the coil did not die instantly) but it is very common that the coil(s) fail in the next few weeks/months. Running at max voltage causes the coils to create internal carbon tracking. Eventfully this will kill the coil. Max voltage is also very hard on the Module that controls the coils. It is pretty common to have those fail also not long after a tuneup.

 

I agree with the masses here and do the tune up first. Coils I would not replace as part of the tune up but if that P0306 comes back after the tune then yes consider the coil.

The P0300 code is my least favorite code to ever have to deal with. Here is why, it is rarely caused by spark and can be caused by about 15 other issues from low/high fuel pressure, to bad sensor readings. and 13 or so other things in between. It is a nightmare to track down. P030# is alot better since it leads you to one cylinder and that means you have about a 50/50 spark/fuel shot there.

Massey

 

Try switching your coil pack with another coil pack and see if it changes to another cylinder. But it dieing after a few minutes is a little strange. That could be your plugs worn out.