My 92 vette ran fine when I first cranked it up (run it @ 20 miles once a month). After it got up to temp it started running rough with no power and the check engine light came on. Took it to Auto Zone to get code read but they could only read 97 and up. Would something as simple as EGR valve cause this? Any ideas? Don't want to take to stealership........Thanks

If you don't have a service manual or followed instructions for blink codes, you should probably buy one of the code readers available. Could be an O2 sensor out to lunch putting you into limp home mode but you really need to find out what the code is telling you.

yea I need to call around and see if there is an auto parts place that can read a car older than 97.....Would a bad O2 cause problems if the car is not warmed up yet? Only had a problem after it got up to operating temp. Also, if I turned the engine off and restarted a few minutes later it would run ok until I started to take off or get RPMs up. Then it would bogg down

Sounds like the fuel pump, or possibly the fuel filter.
You can get the codes yerself, and all it costs is a paper clip...just jumper the "A" and "B" terminals on the diagnostic connector, with the key OFF. Then turn the key on, but don't start the engine. Watch the "Check Engine" light. It will flash any codes it has stored, starting with a code 12, which means it has begun diagnostics. The light will flash the codes. For instance, for the code 12, it will flash once, pause, then flash twice quickly. Code 33 would be three long flashes, followed by three short flashes. It will flash any/all of the codes it has stored, then repeat them until you turn the key off. Check this, and then let us know what you find. You may need to drive it until the Check Engine light comes back on to pull the codes.
hth

Thanks Joel! U tha man! I will try that today and let you know what I get. Thanks

Joel, on my 92 I got a code 13 and a code 65

Well then...let's give it a shot!
Code 13 is an open O2 sensor code, meaning it could be unplugged, broken, or just no good, or it could be a wiring break somewhere in the harness. The drivers side O2 sensor on my '85 blew the center completely out one day!

Code 65 is for the right(pass side) O2 sensor sensor showing a rich mixture at all times.....I think I would start by looking at the sensor, and seeing if it looks damaged, or the wiring melted/unplugged. Several other things could cause a rich signal, including a malfunctioning EGR valve, fuel pressure too high, TPS, ignition problem, MAP sensor, even a saturated vapor canister. But...since ya gots an open O2 sensor code, I'd start there.

Would a bad O2 sensor cause the rich mix?

It could, if it were coated, or carboned up somehow.

It could be a symtom more than the cause but if those are the original O2 sensors, they are overdue to be changed so replacement is a good idea anyway. The accuracy drifts over time. The computer doesn't look at them much until it warms up and depends on the programed temp and conditions which might explain your cold start reset. Note, the one downstream of the cat isn't used for control, just to see if the cat works. That's why the dummy replacement works. Innovatate wants me to re-calibrate my wide band senors every race or every few months as a min. OEM's can't be calibrated that way but when they go off, they will mess up the performance. Two Guys recently did a show based on a bad MAF sensor not measuring accurately in tandem with O2.  You might look for it on line. Could be a bad connection but the wires are stainless because of the heat and the connectors are locked. The bad news is getting them out, especially from a creeper if they haven't been removed. There are a couple of O2 sensor removal sockets that allow for the wires but you might not be able to get leverage in the installed position.