Since I got the fire damaged $50 '91 GT running I have had intermittent check engine lights. The code is 1214 which is an intermittent temp sensor 2 failure (LH computer). The failure rate has been increasing over time. Fails only during or after heavy throttle. Never fails during slow around town or steady cruise at any speed.
The engine harness and all sensors were replaced during rebuild. First I replaced the temp sensor 2 again. No effect. Then checked harness for problems and found the temp sensor 2 connector housing installed backwards on the new harness, so it would not lock. Turned it around and still failed. Then ohmed and examined the wire out to no avail.

I was going to post this to see if anyone else had these symptoms but then remembered that I had installed a 75 C thermostat during rebuild.
Installed an original 83 C thermostat and no more problems.

I guess the steady cooler temperatures during cruse followed by the increased temperature of heavy throttle was sensed as a temp 2 sensor failure.

It's probably my imagination, but the car seems to have more power. Or maybe, the LH was retarding the spark to try to solve the perceived temperature problem?

It makes me wonder, could this be why some earlier LH cars without the check engine light ('88,'89,'90) are down on power? If you are running a
75 C thermostat and have access to a Bosch Hammer, it might be interesting to check.

Others have questioned the wisdom of running a 75 C thermostat for other reasons. A 75C thermostat will not fix cooling problems, so why use them?

I do remember dynoing in Hallet OK with the '88 in 1990 with ambient at 106F. I can't remember which thermostat I was using but, the last and hottest run had the most HP and torque.

To see why my '91 GT cost only $50, go to my website:

Earl Gillstrom '91 GT