ok, I should have just bought an suv.

[BANANA]

Can anyone give me some insight as to why my p5 is only avaraging 18mpg?

Automatic. all stock. 2003 with 43xxx miles. running 205/50/16 size tires, just hada tune up at 39k. where should i even START looking for problems.? (scratch)

O and I dont mash on it either. revs barley exceed 2500. no freeway driving.. got 225 on my last tank

 

[alexelie]

"no freeway driving", and automatic tans. are probably the reason why.

How is the car running? any check engine light?

 

[JCell]

dirty filter?

 

[BOOSTR]

all of the above plus low tire pressure and or stop and go driving.

 

[ucMP3]

Can anyone give me some insight as to why my p5 is only avaraging 18mpg?

Automatic. all stock. 2003 with 43xxx miles. running 205/50/16 size tires, just hada tune up at 39k. where should i even START looking for problems.? (scratch)

O and I dont mash on it either. revs barley exceed 2500. no freeway driving.. got 225 on my last tank

Everything in bold is aiding your bad mpg... Stock tire size is 195 right? Wider tires make for worse gas mileage.

Check your tire pressures, air filter, spark plugs, wires/coils, put seafoam thru your fuel system. You have no CEL right?

 

[Wagonbacker9]

also possible that the brakes are dragging. with so few miles on a 2003 vehicle, it may have been sitting for a while which could help a caliper sieze. has the car been wrecked?

 

[nate0123]

... grabbing brake pad, short trips, lots of warm-up / idling time

how many fillups have you averaged that over, and how do you calculate?

 

[ucMP3]

... grabbing brake pad, short trips, lots of warm-up / idling time

how many fillups have you averaged that over, and how do you calculate?

How many different ways are there? lol

 

[Wagonbacker9]

good question nate... so, i'd recommend you start with air filter, fuel system cleaner, new plugs, maybe wires...

also jack the car up (blocks around wheels) and try spinning each one... if any of them don't rotate freely start shopping for a brake caliper.

How many different ways are there? lol

you can: fill up, then every time you refill divide your miles by gallons, but that only works if you fill to full every time.

i use vehicalc on iphone

you can just track your total miles and gallons

use fuely online..

any number of ways really.

 

[BoostedPR5]

If you have 205/50/16 your mileage isn't accurate anyways so you have no idea what MPG you're getting.

 

[Wagonbacker9]

If you have 205/50/16 your mileage isn't accurate anyways so you have no idea what MPG you're getting.

you can recalculate the mileage very easily... and technically depending on tire wear, its not accurate with stock size tires anyway.

Your mileage is 2.7% (about .5mpg) better than your calculations show it is... due to the car traveling further than it thinks it has.

 

[StealthWyvern]

"no freeway driving", and automatic tans. are probably the reason why.

How is the car running? any check engine light?

I think he has other issues personally... see below comment.

Everything in bold is aiding your bad mpg... Stock tire size is 195 right? Wider tires make for worse gas mileage.

Check your tire pressures, air filter, spark plugs, wires/coils, put seafoam thru your fuel system. You have no CEL right?

I generally averaged about 24mpg in town with my old auto p5. I often took that car to red line.

The worse gas mileage I got on that old p5 was 21.X mpg highway! That was due to a bad primary 02 sensor that would throw a code every once in a blue moon. When I replaced it the gas mileage shot up to 24mpg intown.
Edit: No, I am not saying he issue is a bad 02 sensor.

I don't know if it made any difference or not but my old p5 had a thunder header, simota CAI, motor mounts, aftermarket wheels.

He could have a draggign brake caliper, bad wheel bearings, no idea... without seeing the car.

 

[bazooka joe]

turbo'd auto with 141k miles never got less than 24...something is a miss...you getting a lot of black smoke? any CEL's?

 

[ejb2112]

I'm having the same problem. I used to average 25-26 mpg and now it has dropped down to about 21 over the past year. Some points:

1. 95K miles.
2. Driving habits haven't changed.
3. Tire size (205) hasn't changed. Been wearing them since my first set of replacements.
4. I keep the tires properly inflated.
5. At 89K miles, I replaced the plugs, wires, brake pads, brake rotors, PCV valve and filters (among other things).
6. No CEL's are showing.

My only remaining possibility is the EGR valve. Any thoughts on that? I tried to clean it a couple of years ago, but it didn't seem to do much for it.

 

[Shi-Fu JaY]

bad o2 sensor?

 

[StealthWyvern]

bad o2 sensor?

really the only things left would be 02 sensor (best play is pg for those), clean the MAF, and possibly the coil packs starting to get weak.

 

[Wagonbacker9]

turbo'd auto with 141k miles never got less than 24...something is a miss...you getting a lot of black smoke? any CEL's?

a turbo'd car will often get better mileage than an otherwise equal NA car..

 

[BANANA]

woa, was not expecting so many responses.

To answer everyones questions

1) no check engine lights have been thrown, since i bought the car and had it smogged ( 2+ months ago)

2) just replaced extremely worn tires with new ones, went up a size because they didn't have any of 195's in stock.

3) car is in otherwise pristine condition. Had alignment breaks and wheels checkd when putting new tires on. no drag here. pads are at 60/40

4) not carrying heavy loads. just me in the drivers seat. no rough driving, not many quick trips.

5) last two FULL fill ups ive calculated mgs on fuelly. but previous to that ( and to my tire size uppage) it seamed like my $10 wasnt getting me very far... maybe 60 miles before gas light would turn on.


over all im pretty dissapointed. I mean, even as an automatic in town mpg should be around 22-25. heck, i get 18 mpg in my 96 dodge ram with a 5.9L v8. and at least that beast has some HP.

the only thing i can ting of is that i DO warm my car up. maybe 5 to 7 minutes. only on cold mornings. it takes that long for the needle to reach running temps.

 

[StealthWyvern]

the only thing i can ting of is that i DO warm my car up. maybe 5 to 7 minutes. only on cold mornings. it takes that long for the needle to reach running temps.

excessive idling will kil your gas mielage in a heart beat... try that on your truck and see what happens... You might be lucky to get 12mpg on your truck if you do.

 

[BANANA]

im new to small cars, whats a good amount of time to warm up? in my big v8 if i waited any less than 3-5 minutes it drove terrible. but thats all it took for it to reach running temps. is it not nessary to get the needle up in our p5's? and if it IS why the heck does mine take her sweet time??