Coil problem?

Lots of Dads automatically diagnose problem like this as a coil failure, but why not tell us what engine you have in the Cavalier.

There are many things that can cause this sort of symptom, and you really don't want to start throwing parts at the car. It gets too expensive.

I think you have to diagnose what the real problem is. The possibilities are a lot more broad than your dad's suspicion.

If fuel isn't igniting in the combustion chamber, there could be various reasons for it, not limited to problems with the coil or even ignition. Even if it is a spark problem, it could be a bad plug, spark plug cable, distributor contact, etc.

Ignition problems don't tend to get better at higher RPM. The coil has to energize and fire more times per second the faster the engine spins. But you never know, maybe a bad contact somehow behaves itself under higher RPM. What was the last mileage at which you changed the spark-plugs? Have you ever inspected and changed the spark plug cables?

Then there is the possibility isn't not a spark problem. Maybe one of the pistons isn't compressing the fuel-air mixture. Do a compression test on every cylinder! Compression problems could be less apparent at higher RPM simply because the piston is coming up faster. Think about a bicycle pump for a second. It's basically a leaky cylinder with a piston, right? If you press the pump very rapidly, there is a lot of resistance and you can achieve compression in spite of the air leaking out. In your engine, at 3000 RPM, the compression stroke is happening 3 times as fast as at 1000 RPM, so a slow compression leak won't be as apparent. Also the compression is something that can change with the engine being warmed up due to the expansion of metals, in particular piston rings! Compression can also be lost through valves not closing properly, etc. Imagine if the exhaust valve doesn't close or sit right, at least through part of the compression stroke. What will that do? Blow some fuel-air mixture right into the exhaust.

Could be a fuel injector problem too. Maybe a badly clogged fuel-injector isn't spraying out a fine mist, but squirting out a liquid stream. Hmm, hard to explain why the problem gets better at higher RPM though.

It's a big, dirty, greasy engine with lots of wires, hoses, wheels and belts and things, and it's not running too well. Just ask Dad. :)

What difference does it make. Those general problems that he described could happen in the V6 or the straight 4.

And, to put that into further perspective, doing a quickie web search, I see people are buying the 1992 Chevy Cavalier 2-door Z24 convertible with V6 engine for under 1000 bucks. The four bangers go for next to nothing.

What difference indeed. All engines are just the same, huh;>)

But, we agree that he needs to diagnose, not just change out parts.

That is what it is a 1992 Chevy Cavalier 2-door Z24 (non-convertable) with V6 engine.

Your car has 3 coils. Sounds like bad ignition wires, bad O2 sensors, leaky injectors, and blow fuel pressure regulator have melted down the cat.

We took it to a mechanic and told him we thought it was the catalytic converter.... so he took it out.(He isn't a very good mechanic and he doesn't make any judgments on his own he just does what you say and doesn't check anything so we are looking for a new one) So currently it has a pipe replacing it. It didn't make a big difference in the condition it drives. I don't have a cat anymore. Anything else?

So do I. It might be a good idea to check the individual injectors to be sure that they are sealed and working as they should.

One last thought... do a compression check. See what condition your valves are in.