CEL + Reduced Power Light on 01 Rodeo

I was driving my 2001 Rodeo Sport 3.2L/2WD home last night and it was driving strangely, with my RPMs fluctuating around 200 too high or too low. Anyways, it randomly slows down and my CEL and Reduced Power light came on. I had it towed to a car garage and it came up with these error codes.

PO128-Thermostate temperature too low
PO125-MFR Fuel and Air Metering Circuit
P1295
P1515-Vehicle Speed Idle Control Circuit.

Any help would be GREATLY appreciated.

how old is the battery?

How many miles on the truck?

69,415 miles. I am the second owner, bought it about 2.5 years ago.

The battery is fairly new I believe, I really can't remember.

does it say delco on the battery?

Not sure, the car is currently at the dealer. I can call tomorrow morning and ask, but I do not believe so.

ok, i'll bite Amigo-2k -- what's the point about the battery and brand?

thanks //bc

the +98 came with delco batteries. So if it still has one then it may be original and 6 years old. A weak battery will cause +98s to do odd things.

I would also hope they leak test the intake manifold gasket too. check for the obvious, based on knowledge gained from others.