My car ran hot due to a bad radiator fan. It got all the way to the red zone on the temp guage at one point but once I was able to get on the highway the second fan was able to keep it cool enough for me to get it home. Now I have a miss at around 55mph under load. No miss upon accelleration or idle and also seems to be no miss at higher speeds or as long as I am not in lock up. Could I have burned a valve or maybe just ruined a sparkplug? I cleaned the connections to the coils and it seemed to help some. Now the miss is not as bad, but it is still there.

A burnt valve will cause a rough idle, so that probably is not your problem. Continue along the lines that you've already started, and check out the plugs and wires.

When my '92 SSE L27 burned a valve (#5 exhaust), you could hear the exhaust gases bypassing the valve. It would idle with a little lope, but it would really shudder at 1500rpm @ 50 mph when the torque converter lock-up engaged. FIxed now with 193K on th eclock & still going strong.

IIRC 92 was an EGRless setup that was known to burn valves easily.

On this one.. check plugs wires etc. Experience and being near the red tells me yours could be ok, you should start with the cheap easy checks/fixes.

Thanks, idle is smooth, yesterday put injector cleaner and gas treatment in tank. Thought maybe I got some bad gas or water in the tank. Noticed one of the plug wires was laying on the valve cover, removed away from valve cover. Running better now but will replace plugs and wires if problem continues. Thanks for the help.

We've also noticed that sometimes the rear #4 or #6 wire goes very close or touches the O2 sensor wire. Make sure that isn't happening. Zip tie it away from there if it is.

Thanks, I had caught that also when the problem started and have moved it away from the O2 sensor.