just an FYI if your fuel mileage is down
I've had a Mini Maxx on my truck since the day after I bought it.
I've always monitored ECT and EOT. Here a few months ago, I noticed my ECT was down from it's normal 195-197 to 192. And as I coasted down coming off the highway, it was down to 188.
Thermostats were hanging open.
I had a big drive out to west TX and back and asked my mechanic if I'd be alright. He said yes, but you're going to be down a couple MPG.
Well, I've been nursing the truck for almost 3 months. Just been way busy. I don't idle the truck, and I don't putt around town. If I'm driving, it's at highway speed, and the truck will maintain 188-192 most of the time.
So I'm about to take a 3-4wk vacation in Colorado, and I know I'll be doing a lot of short trips, slow speed/no load, and colder ambient temps, so it's time to get the thermostats done.
Coming home from my buddy's shop last night doing 67mph, ECT was 195-197, and the lie-o-meter showed 19.4mpg
I KNEW what I had going on because I had a good scan gauge type display in my mini-maxx, but without it, the water temp dummy gauge on the dash showed to be just fine.
I DID get a CEL indicating "coolant thermostat performance" twice, but only here in the last month.
If you seem to be down 2-3mpg without any good explanation, I'd monitor the ECT PID and see what your TRUE temp is. You might be due for some thermostats!