What could cause high boost readings and bad gas mileage ?

**jimbo058** · 11-28-2012 12:11 PM

Monday morning while driving to work, I noticed my boost gauge was reading about 10-15 lbs of boost higher than normal. For example, when going up a slight hill, it usually reads minus-10 lbs on the gauge, and it was reading +5 lbs of boost.

The engine did not seem like it was laboring any harder than usual, but I burned about 2 times the usual amount of gas going to work and back. I was just driving along with traffic, not accelerating fast or anything. A 42-mile round trip, combination city-hwy.

The next day, it acted completely normal, with the boost gauge reading like it should and the gas mileage going back up to normal. Since then, I have reset the ECU and re-flashed.

Any ideas what would make it temporarily show way-higher boost and burn up twice the gas ? I eliminated things like parking brake engaged, foot on the brakes.

'09 WRX, Catback, Cobb Stage 1, no other power mods.

**Mikie13** · 11-28-2012 12:24 PM

How does it act during other driving? Take the hill out of the equation.

Thing is, you're not overboosting per say in that situation because you aren't over the target boost...it's hard to say. Something may be causing you to run rich. You should run some datalogs.

**jimbo058** · 11-28-2012 01:03 PM

It was showing abnormally high boost the entire day, like -0- when going down the highway, when it usually reads minus-15. I will run some logs if it acts up again. It is like it was stuck on the "cold-engine" mode or something.

**Mikie13** · 11-28-2012 01:08 PM

Yeah run logs anyway so you can be sure you're alright. What boost gauge do you have? Its quite possible the problem lies within there alone.

**jimbo058** · 11-28-2012 01:49 PM

I have a Prosport "Premium Series Peak/Warning Amber/White with White Pointer clear lens" gauge. I will run some logs and look for rich conditions. Thanks for the input !!!