13 mpg...

[96Vic]

A little background info here, it's a '96 Vic with about 150,000 km (93,000 miles) on it. I'm the fifth owner and have no idea what type of maintenance has been done to it until I got it. It did sit for about six years before I bought it and I don't think that helped things.

Anyways I'm not expecting this car to get great mileage, but 13 mpg seems rather low. I will admit this is almost all city driving with a bit of idling to warm the car up and I haven't been that easy on the gas pedal. The car has also seemed rather sluggish at times and hesitates to downshift as well.

Now I did replace the passenger side catalytic converters just over two weeks ago since one was rusted out. I know one of the O2 sensors was damaged while removing it and I have had a check engine light since then. I was planing on just replacing the damaged one but I've read replacing both of the front sensors can improve mileage.

This would be the correct sensor right? Also are all four sensors the same?

I also plan to clean the mass airflow sensor and change the fuel filter which I'm hoping will help. I inflated the tires to 35 psi since they were down to around 25, I hope that helps as well.

Anyways if you've got any other tips or suggestions they would be greatly appreciated. I like the car, but at the same time it's only a beater and since the body is starting to rot out I'm only planing to keep it until I can afford something better, likely a newer Panther!

[sly]

I'd replace both front o2 sensors just to make sure, spark plugs and give the wires the dark night water spray (from a spray bottle) test. if there are lots of tiny sparks around the wires when you do that, replace the wires too. Of course, changing the oil and flushing the radiator should be top on the list too as well as possibly flushing the brake fluid if it's all crap brown and possibly changing trans fluid and filter using mercon V. 35PSI is what I run in my 93. it works well for these cars. As for cleaning the MAF, MAF cleaner or contact cleaner (if on hand, not sure which is cheaper) only. Also, do not shove anything down the hole in the MAF (straw on the can of cleaner, etc). I generally hold my can about 3-4 inches away at least and just hose out the ports real good from the airbox side.

[HiFiMerc]

I'm only getting 14.5mpg with my 92. It has plugs, wires, TPS, O2's, fuel filter, air filter all less than 3 years old. I've put less about 5K miles on it since all this. Crappy cold weather and lots of warm up idling, then nothing but stop and go driving. That's what I'm chalking it up to anyway. I was getting almost 17 last summer doing the same running.

[sly]

my 93 used to get 19-20 in town with the original engine. most NPI 4.6L should be getting at least 15 (even HPPs with a heavy foot). I would pull off 18 with the NPI and 2.73 gears around town hammering it. my wife would pull off 20 regularly. 26-28 highway. But then, I live in warm country where we just crank it up and go.

[gearheadmm]

I'd replace both front o2 sensors just to make sure, spark plugs and give the wires the dark night water spray (from a spray bottle) test. if there are lots of tiny sparks around the wires when you do that, replace the wires too.

Good advice,
GAP PLUGS TO .030 worth 2mpg.
Remove inlet restrictor in airbox, clean air filt.
Tires to 35 psi.
Lazy O2s made mine suck gas.

I had an auto ranging radioshack volt meter I used to check O2s with back in my dealer days.
If the meter ranged and read O2 voltage it was junk,
If it didn't it was OK.
Some trial on known good sensors would be required for an unknown meter.

Old school vacuum gauge check for plugged cats.
Low idle vac or falling after restart would indicate a problem.
The best way to check is replace O2 sensor with a fitting you can hook up to a low pressure gauge.

[96Vic]

Thanks everyone, I just changed the fuel filter this afternoon and it did help a little with the hesitation under light acceleration. I'll definitely replace the two front oxygen sensors next week and clean the mass airflow sensor. I'll also get around to the spark plugs and wires ASAP. Thanks for the tip on the air box restrictor thing, it amazes me how small the inlet is with it in place. I'm planning to replace the fluids soon as we'll, I've only changed the oil so far. Anyways the warmer weather is coming (hopefully) and that'll help a bit.

[79lincolnlover]

Anyways the warmer weather is coming (hopefully) and that'll help a bit.

Winter is a real drag, especially on fuel economy.

[96Vic]

Figure I should give a bit of an update here. I'm currently getting 14 mpg after replacing O2 sensors, cleaning mass airflow sensor, ensuring all tires are inflated properly. I'm planning to do the spark plugs soon. In all fairness this had been purely stop and go city driving with A/C running and a bit of a heavy foot. Looking it up these cars are only rated at 15 MPG city so for an 18 year old car I can't really complain. I'm honestly debating getting something more fuel efficient as gas here costs about $1.35 per liter ($4.70 USD per gallon for those in the states). I do like the car though and doubt I could find something as reliable and easy to fix.

[gadget73]

Drive around and then walk around the car, feeling the center of the wheels. If one is hot, you have a dragging brake. That will kill your fuel mileage.

[79lincolnlover]

I'm honestly debating getting something more fuel efficient.

New or used? Never choose car payments when you can drive something that's paid for.