I read on club GP it decreases the MPG Is it tru?.Because i manage 12 mpg as is and its killing me.Brooklyn driving is horrible

It could if your PCM isnt tuned for it...


I thought everyone in NY took cabs?

It's not going to hurt it that bad. On a stock GT, I would stay with 195. I'm betting plugs, wires, fuel filter, and o2 sensor would up your mpgs.

Try swapping the 195 back in and see if it improves.

how could a few degrees honestly affect MPG that much, i dont think it can fluctuate THAT much

I used to pretest cars for emissions testing with an exhaust gas analyzer. You would be surprised at the hydrocarbon (unburnt fuel) levels that a stuck open tstat or bad Engine Coolant Temp Sensor can cause.

NO NO.Its not in yet i just ordered it.

So blackarrow you saying i should put it in regardless or am i miss understanding your comment?

misunderstanding* lol

If you're running a stock PCM, and your gas mileage was ok before putting in the 180, try swapping the 195 back in, and see if it improves. If you're running a 195 and it's stuck open, it can hurt your gas mileage, as I recently witnessed with my 95 Park Ave. It was taking ten minutes to warm up in 60 degree weather (not good!). Now it takes 4-6 minutes in 30 degree weather.

i dont have 180 tstat in yet its coming tomorow

Sent you a PM.

Yes, a colder engine is less efficient from a mpg stand point. However, without tuning for the 180 tstat you'll probably bounce between 190 and 195 with the fans. So, it's not going to make a huge difference. As ordonez says, you don't really need it on a GT, it's a knock reduction mod that's more applicable to FI.