Welcome to the SR20 Community Forum - The Dash.
Register
SR20 forum logo

Thread: Loss of mileage

+ Reply To Thread
Posts: 1-10 of 20
2010-09-27 18:41:04
#1
Loss of mileage
Over the past 6 months my mileage has significantly decreased (30 to 20 mpg). However, the car seems to be running fine...no issues except it does appear to be running fairly rich. I know clogged main cat can cause poor mileage, but could that also result in a rich condition ?
2010-09-27 19:00:19
#2
EDIT: Going to take some more knowledge before I state that.

What car, what mods if any, etc.?
2010-09-27 19:07:58
#3
Rich = Probably bad O2 sensor. They go out every 100k or so miles. Spark plugs and wires are a good replacement too.
2010-09-27 19:17:01
#4
Car
O.K. 91 Ser, with all the bolt-ons, including Wolfe ECU. New O2 not too long ago. 240,000 Compression 155 to 158. Original cat
2010-09-27 19:59:43
#5
Originally Posted by Vadim
Rich = Probably bad O2 sensor. They go out every 100k or so miles. Spark plugs and wires are a good replacement too.


i agree. maybe a good cleaning of the maf sensor too would be good
2010-09-27 20:49:34
#6
Originally Posted by GT2871RBLUBIRD
i agree. maybe a good cleaning of the maf sensor too would be good


and regrounding it lol
2010-09-27 22:32:48
#7
Originally Posted by ed
O.K. 91 Ser, with all the bolt-ons, including Wolfe ECU. New O2 not too long ago. 240,000 Compression 155 to 158. Original cat


Any new parts since you noticed the drop in mileage?
2010-09-27 22:53:36
#8
new parts
None...I did have an episode about 6 months ago where the coolant temp. sensor went bad and it took me a while to figure it out. during that time I'm sure the fuel ratio was way rich,as the car didn't "think" it had gotten warmed up
2010-09-27 23:02:57
#9
tune up time IMO
2010-09-27 23:09:21
#10
The stock cat is pretty restrictive, and if clogged, can actually skew the o2 sensor reading. It's likely rich because of the stock cat.
+ Reply To Thread
  • [Type to search users.]
  • Quick Reply
    Thread Information
    There are currently ? users browsing this thread. (? members & ? guests)
    StubUserName

    Back to top