ok, I should have just bought an suv.

[sethro_GT]

Yeah pretty shady deal if he didn't do the plugs, sounds like a "give us money and we'll park your car out back till you come back" type of deal. That MPG is terrible, a lot of good idea's already mentioned. Start keeping a detailed record so you can pinpoint the cause when it finally improves.

good luck.

 

[flash75]

Note the location of the car is in the SF bay area. No expressway driving, automatic. The area where the car is driven is probably hilly and loaded with stop lights. No high speeds. The automatic torque converter probably rarely locks. Most of the driving is probably with the emissions system in open loop because much of the driving is with the engine at less than normal temperatures. All of those things are mpg killers. It's difficult to say the mpg is bad unless you compare it to another vehicle driven under similar conditions.

My 02 P5 is an automatic and I filled it today. It took 6.77 gallons for 140 miles=20.6 mpg. All driving with that tank was in cold weather, no out of town trips, car was parked each time I drove it at about the time it reached normal temp. We have some rolling but not very steep hills and a few stop lights and intersections with stop signs. Usually I get better mpg because I almost never use a tank of fuel without one or two out of town trips. Normally with about a 50/50 mix of around town and out of town driving I get from around 24-26 mpg.

Different driving conditions can make a huge difference in mpg. BTW, there is nothing wrong with my car.

Clifton

 

[BANANA]

those gaps are DOUBLE factory spec.... they can't be original unless both sides of the plug were just worn that horribly... in any case, oh my god... if changing those doesn't help... NOTHING will.

Well, that hits the nail on the head. The boyfriend is going to wyotech to be a mechanic, he said it looked like they were just TERRIBLY worn. and with about 43xxx miles on the car.. about right if they had never been changed. On a side note, the new Plugs I got were NGK Laser Platinums. Anyone used these before? supposedly good plugs increase peppyness and economy....well see about that...


Also, though I do live in the SF bay area, I do NOT live in San Fransisco. Not any hills where I live, except when I do a mountain drive with my buddies ( and I'm not factoring those tanks in my calculations. I'm sure that kinda driving gets terrible mileage, and honestly, I don't care! its fun!)

Regardless of her mpgs, I still love my little p5. thanks for all your suggestions guys! will continue to observe and report

 

[Wagonbacker9]

I'd recommend an NGK ZFR5F-11 platinum plug... I run the same plug in the next heat range up in my MSP and am VERY happy with it.

 

[sethro_GT]

I only use NGK base model plugs (with the V cut). I think its been proven that there is no benefit from the "fancy" plugs but correct me if there's data to show otherwise.

 

[BANANA]

so far the new spark plugs have given me an extra quarter of a tank! woo hooo

 

[Magus]

Make sure they are NGK's, and not bosch anything!! I ran some in my ford escort and p5. The plugs killed the escort, and throw a cell on the p5. I changed to ngk v-power copper and never looked back.


Platinum is sort of a waste on the P5. The point of the Platinum plug is that it should last longer before needing to be changed. That would be great if the P5 was not tuned from factory to be rich. That means that the plugs need changed more often than other cars because of tune. So plain cheap copper v-power NGK plugs are just fine and are OEM. The wrong spark plugs and wrong gap will definitely kill mpg. But as you have noticed, how you drive also has a lot to do with it. Winter gas will kill mpg, as will gas with e10 (most). I had a gas station that did not have any or very little ethanol and my mpg was the best.

I would recommend simple mods that help with power. Since you have wider, taller, and sticker tires it will hurt mpg by 1 or 2. I fixed that with the Injen styled CAI. It goes into the wheel well and produces a bit more power. I made sure to put a AEM bypass to keep from hydro locking. I have had friends with short ram intakes that have hydro locked. I have had the car for 5 years and no water issues. Other things like taking the roof racks off helped with the whistle and aero (slightly better mpg). Make sure your car is clean and waxed.


Just understand, the more power you have the less the engine stains. It means better mpg.

Just to give you little hope.....

started with 29 mpg on highway and 24 city

peak with little to no Ethanol gas, my mod list, using AC, and driving 55 mph is what is in my profile.

 

[BANANA]

Update time, more questions.

Thanks for the advice magus, was actually very informative. a k&n intake is on my list, would that be along the same lines as the injen?

and as it turns out over the last three tanks I haven't avaraged ANY gain. The tank SEEMS to last longer, and i get to about a quarter tank at 220- 240 miles (this is WTIH freeway driving now). I start to think its getting better, then the next time I turn on my car the GAS LIGHT has suddenly turned on! happened to me just this morning. started the car with just over a quarter tank, 240 mi on the trip meater. got to work about 4 miles later, turned the car off. 2 hrs later had to deposit money from work at the bank (less than a mile away) and suddenly my gaslight is on. How do i go from half a tank to E? Is the float getting stuck or something?


what the hell is wrong with this car?

 

[JamesCH]

Do you have a heated garage, and do you park in an outdoor parking lot at work?

Gasoline expands and contracts a lot with temperature. I recall stories of Arizona drivers filling up and then topping off their fuel tanks, driving a bit, and then having gas basically gushing out of the filler because the gasoline had expanded so much as it warmed from the 55F of the storage tank to the 110F it was outside.

Maybe your gas is cooling down after you park it in a cold lot and registering lower. I've noticed that in my MS3, I'll fill up when it's 32F and then drive when it's -10F and suddenly I'm down 1/8 of a tank or so.

Just a crazy idea (shrug)

 

[RABID_MP5]

Is performance OK? I'm wondering if the auto or torque converter could be amiss, tho not sure exactly how.

 

[drgnzadiel101]

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?

ummm no. he wouldnt even be below 21mpgs. 18mpg is h22 status and that is a performance motor

 

[StealthWyvern]

OP, I dont know if this has already been answered but how are you calcutating gas mileage? Also do you have a heavy foot when the car is getting upto op temps. I assume your have done all the basics like filter, plugs, wires, coil packs, fuel injector cleaners.

Also when I modded my old P5 I didnt see any difference in gas mileage going from a 195 to a 215 wide tire not did I put put in a CAI or 4-1 header, or even LW pullies.


Edit: Yes I am fully aware that i at one time and point posted in this thread. However I am not going to go back and re-read all 5 pages of info.

OP, I don't know if it makes any difference to you but you can't go by the gas light alone. Between my old p5 and my MSP the gas lights come on at completely different times and its the same size gas tank. My old p5 the gas light would come on around 260-280 per tank and my MSP generally comes on around 280-320 but generally 280-300 seems to be average.

Make sure they are NGK's, and not bosch anything!! I ran some in my ford escort and p5. The plugs killed the escort, and throw a cell on the p5. I changed to ngk v-power copper and never looked back.

I wounder if you werent running the incorrect gap on the escort.. my old escort ran perfect on bosh plugs..... all my fords seem to prefer bosh plugs... put bosh plugs in the old p5 and it ran like s***. Now put NGK's into my ford and it runs like crap. Its werid how that is between makes.

 

[BANANA]

I park on the street both at home and at work, so temps are constant.

and thats ok, i wouldn't wanna read all 5 pages either =p

Ive performed the spark plugs and filters myself. supposedly the car had a "tune up" about 3k miles ago for the 40 k service, where i *ASSUME* they performed the necessary adjustments.but concidering they haden't done the plugs i have my doubts. My next step is Seafoam, but im unclear about the specifics.

the gas lights is just my indicator of when to fill up. But for actual mpgs ive looked at my total miles driven divided by how many gallons it takes to fill up until the switch shuts off on the pump. the gas light has been pretty consistent coming on when i needed around 12 gallons. what gets me is how i go from registering 1/4 of a tank to the gas light coming on in less than 5 miles. wtff???

also, before i started filling up and was only putting around ten dollars in, i used to average about 60 miles before the light came on again. and that 10 put me at about 1/4 of a tank. so Realistically when i drove to work with 240 on the tank and a quarter left, i should have had about 60 more miles to go BEFORE the gas light came on. ( i know our cars have something like a two gallon reserve, but ive never run it down that far).

also, im gentle on the car when its running cold. I don't excellerates hard very much at all, and i keep the revs down until its at operating temps.

so a) whats up with 20 mpgs freeway and in town driving and b) whats up with my gas meter?

what things should i try next? arggggh.

 

[StealthWyvern]

so a) whats up with 20 mpgs freeway and in town driving and b) whats up with my gas meter?

what things should i try next? arggggh.

Well all things considering you only really have a few things to replace/test. Your MAF, FPR(fuel presure regulator),and your 02 sensors. My gas gage is also werid from 1/4 tank to E when compared to my old p5. Both cars acted completely different when comparing the gas gauges to one another.

 

[c4racer]

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

My wife got closer to 22-24 range in a 70/30 mix of city / highway driving around the South Bay area in her 2003 P5 running same sized tires. Did not seem to change much with mileage, car now has 120K on it. FWIW.

 

[BANANA]

see thats what i dont understand, the car only has 44 k on it. so realistically the engine should be running much cleaner than it is. there are ppl on this forum who drive spiritedly with twice the milage i have on my car and are getting above factory estimates.(dark)

 

[EVADE]

try CRC Enigine MAF Cleaner

 

[bestbiker]

HOLY CRAP!!

after 11,000 miles of driving the car, I finally am getting better gas mileage.

69,000 miles on the car, I took to get the catalytic converters checked because I just found out about the federal warranty that covers them to 70k even if dealer warranty is expired.

The cat wasnt plugged, but the computer readout was showing spikes on the second 02 sensor, meaning something was wrong with it. it was running 180 degrees C cooler then the other one in the same spot.

ALSO- the fan control modules on these were bad in the 04 ish year range, causing it to kick on and off, or sometimes not turn on at all

after both of those were replaced, i went from 22 to 26.5 on the highway driving 75 (eekdance)(eekdance)(eekdance)

hope that helps!!