P0128 code every 3 or so months

[GTPNovak]

I bought the GTP Daytona 2000 with only 65k miles. I know the history of the car from 28k. All mods were done before that. It had a pulley (unknown size) till the supercharger needed to be replaced around 30k. The thermostat seems to be stuck open or doesnt have one (runs 160 or less while driving can get to 175 in traffic), so i plan to fix that. Could that be the issue with the code or is the sensor bad too?

I research the thermostat a bit and learned that it has an offset to it so the type i buy could be important. Do aftermarket ones work or should i go with the GM. I do plan to put a pulley on this summer.

I was wanting a Robertshaw or similar style as they have higher flow.

This car is so much fun to drive and i have learned so much from reading on this forum. Thanks for all the great detailed information!

[SgtMarshal]

I got that code when I started driving in the cold, and forgot I had a drilled thermostat. the thermostat could be stuck open, in which case, I would replace it. you can get a 180* thermostat and delete the code, or just run a stock oem one and not worry about tuning the code out.

[GTPNovak]

So are you saying if i get a colder thermostat 180 i will keep getting the code and just clear it when it comes on?

Also if i get a custom tune can that be adjusted to a new temp? I saw a member on here makes a tune to your cars mods for what i think is cheap 100 or so.

[SgtMarshal]

all that happens to adjust the tune for the colder thermostat is to set the engine code P0128 to "no report." it's pretty standard practice because a lot of people run a colder thermostat. you can keep clearing it if you want, it's not that big a deal.

[Fivefingerdeathpunch]

There is no gain to be had from running 10º cooler, I'd just slap a new 195º in there and call it good.