Peculiar Gas Consumption @ 3k+ RPM

Sorry about the "thread jacking", I posted a new thread about it.

I remember finding the sensor in a picture and it appears to be on the hot side like you said which makes sense if there is only one. Some guys are installing aftermarket gauges but I was wondering if I could install a gauge and use the stock sensor output for the new gauge while leaving the stock gauge still attached maybe just calibrating the new meter for the sensor . Basically two circuits in parallel, or would that drain the circuit too much or interfere with each others circuits. I want to avoid cutting and splicing a coolant line but I will if I have too. In the mean time I guess I'll keep a good eye on the gauge but it has never moved above the mid mark and I'm afraid of missing it if it happens fast. Does any kind of light eventually go off or does the mill just respond to some other failure after all my fluid drains out or get blown out the tail pipe like my 626 did.
How does higher mileage affect over heating ?? Just old parts breaking ??
I'll post in my other thread about this now.
Thanks

I have an 03 auto and whenever I go over 3k (~70mph) I get horrible milage, 36 mile trip can cost me around a quarter of a tank or more. It's weird bc when I drive sometimes on that 36 mile trip to my girlfriends house, if I go 80-90 mph I get better milage and the gas gauge barely moves. Astounding.

I've decided on this

http://www.ultra-gauge.com/ultragauge/index.htm

fast cheap and easy no cutting

Jordysoso said:

I have an 03 auto and whenever I go over 3k (~70mph) I get horrible milage, 36 mile trip can cost me around a quarter of a tank or more. It's weird bc when I drive sometimes on that 36 mile trip to my girlfriends house, if I go 80-90 mph I get better milage and the gas gauge barely moves. Astounding.

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I, believe it or not have done the exact same thing. When my girlfriend went to college (1.75 hour drive) If I did the speed limit (65) I'd be damned if I got 26mpg. Cruise Control and flat. Filled up right before leaving, hauled ass home 80+ the whole way and filed up when i got home: nearly 33 mpg. I've done it several times and got the same results, even switched up which way i went fast on as a challenge. (bang)(gah)

I looked at my MAF sensor, I couldn't remove it from the top, so I just disconnected the airbox. It appeared clean, but I sprayed MAF sensor cleaner on it anyway. In the process of removing the airbox, I noticed the rubber tubing was ripped where the tubing flexes between the throttle body and the airbox. It was self-disintegrated in multiple areas, not cut. I taped it up with duct tape. Ghetto temporary fix.

70 MPH is around 3200 RPM.

pcb said:

You just need a girlfriend that likes it fast. I know girlfriends are expensive but that sucks.

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She likes going fast.(no jokes intended) around 100-105 she gets a tad nervous or really windy roads once you hear a tire chirp..

I just double-checked, for those who want to know without driving.
Cruising at 70 MPH is 3100 RPM. Cruising at 55 MPH is 2500 RPM.

the car's rated 24 city/30 hwy iwth the auto, not sure what that is in metric but in my experience it's pretty easy to get that. I've got a scangauge2 to watch real time economy. overall the car's geared horribly for economy (when you can pass w/o downshifting, it's not geared for economy at all). I've gotten 30+ in town and stop-and-go traffic with the sport-shift auto, feathering the gas and short-shifting the crap out of it so I don't doubt that it's capable of high city mpgs esp with the manual. but I'd like to hear more about the cars getting over 30 at any speeds over 70 mph (roughly the OP's 3k rpm) because at that point, it's up to aerodynamics and BSFC tables.

I've also noticed I can get better mileage on the highway myself than with cruise. I know from school and reading that cruise oscillates the speeds but this is the only car I've ever been able to see (GPS mpg varies 1-2 mph, scangauge shows (at 70) swing from 23-40 mpg on flat ground (averaging 28-29) while I can hold 29-32 (averaging 30)

even on the highway, manuals are better than autos with the TC locked up 9 times out of 10. comes from fewer moving parts, no pressurized lube system, etc. only reason autos get better fuel economy is they're geared taller in the last gear(s).

As for the OP's original intent: fixing the car... slighltly plugged exhaust could do it. Something where you're not trying to move enough CFM in town and have the coast-down time to compensate while on the highway, it's all under power. Could also have to do with aerodynamics: anything missing/bent? sagging rear springs? roof rack cross-bars? I kind of doubt it's mechanical drag, that'd be noticed around town too. I can think of a number of things to check with a scope or scanner (live data, not just generic codes) but if you had them you wouldn't be asking us.

I haven't checked back in a while but thanks for the replies. I'm definitely going to get a clean air filter because yes, it's disgusting. And I'll also get the MAF cleaned. I've been tempted to start adding some aesthetic mods my P5 but I'm concerned about whether or not it would worthwhile on a car that is already at 160k km.

Thanks again for the tips.

I replaced my air intake tube because it was cracked. After replacing it with a new one, I am getting a little better fuel economy. I can cruise at 70 MPH and get 28 MPG so that is about a 1.5 MPG improvement.