I have had 16-18MPG on this car (1992 SSEi) since I bought it about 2 years ago. I take my MPG at every fill up so these numbers are accurate. I live in Northeast Ohio. It is winter now, but MPG was about 17 during the summer. This is mostly city driving (about 90-95%). Over the past 2 years I have done a lot to this car. Here is a list of everything with dates.
1. Heater Core (Summer 2006)
2. SC drive unit (Fall 2006)
3. 190 Thermostat (Fall 2006)
4. Replaced all hoses (2006)
5. Gas tank (12-28-06)
6. Gas straps (12-28-06)
7. Cam sensor (4-23-07)
8. O2 Sensor – AC Delco (4-26-07)
9. Fixed hood + trunk light (4-26-07)
10. PCV Valve and O-ring – AC Delco (5-9-07)
11. Starter (11-1-07)
12. Oil pressure sensor – Junker (11-1-07)
13. Replace LIM, SC, and TB gaskets. (Winter 2007)
14. Cleaned TB, SC, and LIM in parts cleaner. (Winter 2007)
15. Cleaned MAF Sensor (Winter 2007)
16. Front right wheel bearing (1-11-08 )
17. Monroe Struts, mount, bearings, and boots. – Both front (1-11-08 )
18. Wix Fuel Filter – 128,000 miles (1-11-08 )
19. Turn signal flasher (1-11-08 )
20. ELC Air Compressor relay (1-13-08 )
21. NGK TR55 Spark Plugs (1-21-08 )
22. Autolite Pro Spark Plug Wires (1-21-08 )
23. Removed both rusted support rods from exhaust pipe. Welded a rusted/broken bracket back to the exhaust pipe. (1-21-08 )
24. CAI. Rx-4750 K&N Filter. Polished aluminum pipe. Silicone 3.25 to 3 coupler. IAT drilled into filter. Spliced IAT harness for it to reach. (January 2008 )
25. Driver door lock actuator - Junker (Summer 2007)
-Oil and oil filter is changed regularly.
-No current leaks.
-MPG is mainly on the low side near 16. Driving like a grandma and even with some highway driving and it STILL keeps it around 16-17.
-Notice cam sensor date, car was driven with the bad cam sensor for about 6 months.
-One of the belts had a hose clamp grinding into it so it is slightly worn in the middle. Will replace it sometime soon. Doesn't seem to pose a problem. It was grinding for about a month.
-Car was driven with memory steering for about 1.5 years. Fixed once I did #17.
-Junker oil pressure sensor has died. Car reads over 120 oil pressure constantly again. Learned my lesson and will be putting a new one in in the summer.
----------Current unknown problems/ may be associated with MPG-----------------
1. Weird ringing noise while driving AND in park/neutral. I have not had myself or someone else check the flex plate or transmission for it yet. http://www.bonnevilleclub.com/forum/...hlight=ringing
Note: #23 above, I believed the exhaust pipe to be the ringing problem, but this didn't help.
2. Grinding noise at idle (800 RPM). Lower the RPM, louder it is. Goes away with any acceleration. Possible Harmonic Balancer? Sounds more like its coming from the supercharger, but we rebuilt the drive unit and replaced the oil at the time.
3. Grinding noise that correlates with acceleration, mainly lower rpms. Not present at idle. Seems to make the noise while in park/neutral. This problem was not present with problem #2. So the cause should be separate. I noticed the pulley above the harmonic balancer seems to move left to right a bit while running.
4. Dash display with mileage, car picture, etc. will sometimes flicker. It may even go completely blank. This is rather uncommon and happens more when its cold and/or wet out.
5. Do we have 3spd transmissions? I have watched my RPMs and it only seems to switch to 3rd gear. ALSO - when i'm driving at a consistent speed and my car kicks into overdrive it has a pretty bad bucking to it. Knocking it out of overdrive by more acceleration or deceleration stops it. (2000RPMs....then it ,from what I believe, kicks into overdrive and goes to about 1500RPMs) This hesitation only happens when it kicks down to this 1500RPMs.
Thats about it boys. I have given you so much information because I want to at least let it show that I have done my homework and am not expecting you guys to do everything for me here
I was thinking cat. converter which i don't mind buying a Magnaflow if I have to. I'd just rather pay for a welding job for it once I have the money for a new exhaust system this summer. It sounds hollow, but its probably the original.
Any ideas for my bad MPG? Or even for my other possible problems if something comes to mind, but i'm mainly worried about my MPG since its constantly costing me money.