1996 3.8L Camaro (base)
249k Miles
New:
spark plugs
spark plug wires
fuel filter

Never had serviced:
Catalytic converter (original one)

NOCHECK ENGINE LIGHT AT THIS POINT (no check engine light when i went to BIG O)
My car chugs at full throttle, 3/4 throttle, and have to lightly step on the gas pedal. has a BIG LACK of power and chugs down the road. Had it tested at a BigO, they diagnosed this.
- Engine misfire, spark plug 2 OR
- bad coil pack (2 n 5 pack) OR
- dirty injectors

NOW CHECK ENGINE LIGHT AT THIS POINT (visited autozone with check engine light)
Went to AUTOZONE, obdII scanned it came out with...
- engine misfire bank 1, spark plug 2
- catalytic converter inefficiency.

So i cleared the codes. the check engine light is no longer on. BUT i suspect it is the coil pack. i did some googling for the fire order, since i cant seem to find my chilton book, and a forum said firing or was this:

6,2,5,3,4,1 . which when i was at autozone, the guy brought it up on the computer that 2 was at the end of the firing order. im confused.

Questions:
--- What seems to be the problem with my car?
--- What is the correct firing order?
--- Should I get a new catalytic converter? because of the smell (needs smog right now)?
--- Has my O2 sensors crapped out because of the misfire?
--- Why does my car smell really bad, sometimes like gas?
--- Are Coil packs easy to change?

Please help me out, i have limited funds, and need to pinpoint the problem.

 

That's alot of miles on the original Cat. Sounds like it's time.

 

Every 100,000 miles the O2 sensors should be replaced. Have you ever had a througho cleaning of the injectors? The injector could be clogged. If the cat is clogged or dirty, you should have a foul rotten egg smell under heavy accelleration. The coil packs have two bolts holding them in and the connector just unplugs with a small clip. Get some sea foam. Start your car in park and put the emergency brake on. Take the brake booster vacuum line off and leave the one way check valve in the brake booster. Put your finger over the vacuum line so it doesn't stall out and then slowly let your finger off and stick the vacuum line in the bottle of sea foam. That will clean out your injectors, valves, cataylitcs converters, and O2 sensors.

 

Being that the scan shows only one plug misfiring, I don't think it is the coil pack. Each coil fires 2 plugs and if it were bad both plugs would misfire. Check the wire and plug for plug # 2 cylinder, better yet, change all plugs & wires. The coil pack is marked with the spark plug number. The firing order for the 96 3.8V6 is 1 6 5 4 3 2 . The downdream O2 sensor is complaining that the cat is not working right, but it could be due to the misfire. Once u clear up the misfire see if the cat still shows bad, if it does it will need replacement.

 

You can check if the coil pack is bad. Check the secondary resistance and the primary resistance. You'll need a multimeter and switch it to the OHMs mode and then put one electrode on each of the towers. That checks the secondary resistance. The primary resistance is checked by putting the electrodes on the connector. I can't think of the propper OHMs for each, but it should be in your chiltons or haynes manual.

 

all plugs and wires are changed. i forgot to mention, i agree that if the pack was bad both would misfire and at bigO they said the same thing, but only #2 was misfiring. and the day before i took it to them i just changed the spark plugs and wires. so i know its not those for a fact. THANX for the tips, i will change the cat out and see if that's the problem!!

 

The misfire could also be due to a bad injector, so you may want to check if that injector is getting fired, or leaking, or not opening.

 

I just went through the same thing. The #5 cylinder was showing up as a missfire. You are corect that one coil pack fires two plugs (waste spark) is the term, every time the coil fires it sends energy to both of the plugs but the cylinder on the power stroke is were the work is done. So the coil can be defective on only the one cylinder, I bet that if you changed the coil pack the missfire will go away. At least it solved my problem.

Marc

 

You could try swapping the coil packs to see if the misfire will change cylinders then.

 

All the times I see people reccomend to 'Sea Foam your engine' no one mentions to be cautious in doing so or severe engine damage could occure. (hydrolocking) Me? I prefer using Chevron Techtron fuel treatment to clean the top end and injectors. It really does work.

At 249k the list of things to check gets rather long: Intake leaks manifold, hoses), sticking EGR valve, valve clearance (Yes, I know hydralic but parts do wear), O2 sensors, rear muffler (internal collapse)....

I really suggest havinga Full diagnostic scan done when on the roll, even if you have to pay for one. If you owned the parts store, swapping out parts till you finally find the problem may be cheap, but if you have to earn your $$$ it's cheaper to spend it wisely.