Is there anyone out there driving a 95 SSEi that gets less than 200 miles per tank? The reason I ask is because my son drove my car during the last week and that'* what he averaged. I know I know Boosty, he'* 17 and he likes the boost gauge, but come on that mileage sucks. I know when I drive it, it never even gets close to getting near boost and I don't get much better mileage than that. The engine light shows IAT sensor which thanks to Boosty will be replaced at NEBF but that can't be the reason for such poor gas mileage, and yes it'* been like that since I bought it last year.


PS, there are absolutly no mods to this car.


Thanks

A SSEi should almost get the same MPG as a NA

unless you get into the Boost then well you know

I luv that fact that the car is */C but I never use the boost........well maybe once every 4 months, and I don't even floor it. Bottom line, the 90 SSE with twice the mileage on it got more then twice the mpg as the 95 SSEi.

I think that there is definite room for improvement there, Frank.

I assume that you have gone over the car and done all necessary standard tune up items, right?

Of course, the IAT sensor IS an important sensor and one that is working improperly or not at all, just might be wreaking havoc with the PCM enough to make it run at default values.

The only two things I have not changed in regards to tune up items is PCV Valve and ignition wires, since the pcv was rattling just fine and the car isn't missing or the wires aren't arcing although I will change them at NEBF. I understand what you're saying about the IAT lash, but I doubt that when it'* replaced it will increase my mileage by 150%.

When I refer to the mileage listed, this is with the trunk empty and usually no passengers, althought it'* strickly city driving which still is very bad MPG.I don't think anyone on this forum gets worse mileage.

LOL! I agree that you should not be expecting 150% improvement with an IAT replacement. It should only be about 148%.... J/K... :P

But seriously, any time someone says that their gas mileage is terrible even though the car "seems to be running fine", the first thing I want to look at (if there are no codes or other obvious problems) is the tune-up status. Which BTW, brings up the obvious question, have you read the codes and/or had it scanned for all possible stored codes?

OK, so here'* a minumum of what I would want to ensure was done, if this were my car:


1. Exhaust. Review your manifolds, downpipe and exhaust pipes for cracks, breaks, or pinholes. While the S2s don't have as much problem with this, you DO live in the great white north, with it'* accompanying rust. Fix any problems found.

2. High Flow Converter. Replacing your converter is a great way to regain the performance of your vehicle, IF you have a reason to suspect that it is partially plugged. Over time converters can become plugged up and greatly reduce fuel economy.

3. Air Intake. Replacing a dirty stock air filter is a great way to recover your fuel economy. Another bigger approach would be to replace your air filter with a high performance intake kit or aftermarket drop-in.

4. Spark Plugs. Pull and review your plugs. Take pictures if necessary. Dirty, worn, burnt or improperly gapped plugs WILL affect your mileage and performance. Replacing platinum spark plugs with some high performance iridium spark plugs or NGK coppers may also increase fuel economy.

5. Tire Inflation. Keep your vehicle'* tires properly inflated. Low tire pressure reduces fuel mileage and increase tread wear. It is estimated that you can lose up to 6% in fuel efficiency.

6. In Tune. Keep your vehicle tuned up. An engine that runs roughly or misfires from plugged fuel injectors, bad spark plugs or wires, or worn and corroded ignition components will suffer from reduced performance and fuel mileage.

7. Stay Balanced. Keep your vehicle rolling smoothly. Make sure your vehicle'* tires are balanced, the front ends are aligned and the brakes aren't dragging. The added rolling resistance from improperly adjusted tires, brakes and alignment can cut fuel economy by as much as 20 percent.

8. Oxygen Sensors. Check your O2 sensors. A new oxygen sensor alone can improve gas mileage by as much as 15 percent, just don't use the Bosch sensors on your Bonneville.

thanks for the write up lash and I will reply to all


1. Most of the exhaust system is less than 2 years old. Previous owner replaced it before purchase.

2. I have no reason to suspect the cat is bad, since it starts well with no rotten egg smell at any point in time and there is good flow at the rear pipe.

3. It has a brand new stock Fram air filter when I did the tune- up 2000 miles ago.

4. I installed new NGK plugs when I did the tune-up, */C coupler, LIM, UIM, change.

5. Tires are approximatly 20% worn and inflated at 32 psi.

6. Only plug wires and PCV not changed during tune-up.

7. Tires are balanced and no vibrations noted on highway.

8. O2 sensor was replaced during tune-up with A/C delco thanks to Peterg2000.

The only code read was for the IAT sensor.

Brakes?

New:

Front rotors, pads, rebuilt calipers, both front wheel bearings, emergency brakes and rear pads.


This is the list of parts I purchased and ulitmately installed last summer.


Interior Bulbs
Rear Vents
Spark Plugs NGK
Gas Tank, Strainer, Fuel Lines, Fuel Filter
Air Filter
Engine Coolant
Front Hub Bearings (Both)
Front Rotors, Pads, Calipers, Guide Pins, Bushings, Brake Fluid
Transmision Filter, Gasket, Oil
*/C Coupler, gaskets, Oil, Nose Drive Bearings
Nose Drive Drain
LIM Gaskets
Engine Degreaser
Engine Oil, Filter
GM O2 Sensor
Rear Linings
Emergecy Brake Cables
Throttle Positioning Sensor (Used)
Valve Cover Gaskets
Undercoat
Remote Entry Fob
Right Front CV joints and axle
Thermostat & gasket
Accessory kit

Ah, yes, it'* all coming back to me now...

All I know is that sum-pin' ain't ra-ight.

There has to be a cause or causes.