I am a new corvette owner. In February I purchased a mint 1992 Bright Red Coupe with only 21,000 miles.

Recently I have encountered 2 separate problems.
The first is the A/C. When summer first hit, I would turn on the A/C and it would work wonderfully. Then a couple weeks later it stopped blowing cold air. I checked for an error code as the owner's manual instructed, and it showed error code 09. Apparently this meant "low freon". I have the two very large repair manuals for the car, but couldn't find a single place that told me where to put more freon (I know it's not called that anymore). I was also told that cars don't "use" freon, and if it runs out, that means there is a leak.
I'm not sure what the previous owner had done, but he had the A/C serviced last summer. Is it possible he had it switched to the new R134A, and if so, how would I know? And where do I fill up my refrigerent?

I know nothing about A/C, what the parts look like or anything unfortunately...

The second problem I think is ignition related. The car normally runs awesome. It starts great, takes off when I step on it, etc. But three separate times now, in the past month I have had the "service engine" light show up right after I start it. When this happens, it sounds like it doesn't want to start for a second, but then idles ok. You can also hear a very loud fan running, which I normally don't hear. This has only happened when I drove it, parked it for about an hour, and then started it. When it's parked for a long time, it doesn't do it.

When I drive it with the engine light on, it totally lags, and won't rev too high. But after driving with the engine light on for a couple minutes, the light turns off, and I can immediately drive like nothing ever happend. I'll step on it, and it takes off like it should.

Is this the dreaded optispark problem, or is something else going on?
As you can tell from the mileage, the previous owner only drove it for joy-rides every week or so, but since I got it in February, it has become a daily driver.

I previously owned an '87 Iroc Camaro with an L98, and have basic mechanic skills, and am familiar with main parts of an engine, but I'm new to the lt1.

ANY help or advice would be very appreciated. Thank you.

 

if the gas ports are threaded then it's still R12. If they are a quick connect then it's been converted.

you need to check the codes for the engine light. There are many posts here about that process.

 

Some pictures will help identify each type, R12 = old freon) 134A= new freon.
The high and low side fittings will be found on the A/C plumbing lines near the power steering reservoir. Both types often have a plastic dust cap installed, pictures here show it installed and removed.
Note that the threads visible on the R12 fittings (first three pics) are external those visible on 134A fittings are internal.











If you have NO tools or experience working on air conditioning, consider having a pro do that work, at the minimum a good set of gauges matched to the freon type should be used, adding freon using the charging hoses sold at parts stores can be risky and dangerous.

For your running issue, see this link to pull the engine codes yourself using only a paper clip:

http://www.corvettebuyers.com/c4vettes/ecm.htm

For best results troubleshooting any codes retrieved follow the flow charts in your factory service manual (book #2) the codes do NOT indicate a part is bad, only that there is a problem in that electrical circuit. The tests in the flow charts help isolate the cause, they usually require a digital volt ohm meter (DVOM) to perform the tests indicated.
Many issues are due to poor electrical connections and do not require part replacement, good luck.