Tim Groth
SCCoA Member
My daily driver 89 SC w/ 218K miles has poor fuel mileage..I average 13 miles per gallon which isn't ideal. Given the car owes me nothing, and since it is cheap to insure I accept it. Just looking for some direction as to what I should consider replacing to improve the mileage. My usual commute is mixed highway and city - 20 miles either way per day.
Also for what it is worth, the fuel mileage took a dive after the head gaskets blew at 200K. I deleted EGR at this time, the EGR sensors were hooked back up and capped off (read/heard this keeps the CE light off...it has for the most part). Would this have any impact? Also there is a small exhaust leak before the O2 sensor where the down tube attaches on the passenger manifold.
Since it will be asked...here's what has been replaced or done to the car in the last 20K or less.
New Plugs - Autolite XP103s
New Wires - Autolite OE Replacements
New Oxygen Sensors - Standard Brand (el cheapo's off rock auto)
Cam Sensor - BWD OE Equiv
SCP Down Tubes
High Flow Aftermarket Cats
Air Filter Cleaned (Spectra Cone Filter)
DIS was re-seated with Artic Blue
Car runs smooth 95% of the time. Sometimes at start up it run like a 4 cylinder and then it smooths out after 1 min...not really sure why this is...or what the check. Not usually anything that throws a CE light.
CE Light was on 24/7 - After O2s replaced it went out - now it stays off for 2 or 3 days...comes back on, then goes back off.
Do any of the sensors never spoken about have impact on mileage...i.e Map Sensor, IAT Sensor on the Rear Plenum?
-Tim
Also for what it is worth, the fuel mileage took a dive after the head gaskets blew at 200K. I deleted EGR at this time, the EGR sensors were hooked back up and capped off (read/heard this keeps the CE light off...it has for the most part). Would this have any impact? Also there is a small exhaust leak before the O2 sensor where the down tube attaches on the passenger manifold.
Since it will be asked...here's what has been replaced or done to the car in the last 20K or less.
New Plugs - Autolite XP103s
New Wires - Autolite OE Replacements
New Oxygen Sensors - Standard Brand (el cheapo's off rock auto)
Cam Sensor - BWD OE Equiv
SCP Down Tubes
High Flow Aftermarket Cats
Air Filter Cleaned (Spectra Cone Filter)
DIS was re-seated with Artic Blue
Car runs smooth 95% of the time. Sometimes at start up it run like a 4 cylinder and then it smooths out after 1 min...not really sure why this is...or what the check. Not usually anything that throws a CE light.
CE Light was on 24/7 - After O2s replaced it went out - now it stays off for 2 or 3 days...comes back on, then goes back off.
Do any of the sensors never spoken about have impact on mileage...i.e Map Sensor, IAT Sensor on the Rear Plenum?
-Tim