1990 GXE, 90,000 mi, auto. Getting about 18mpg. Dads car. He said it used to be better before.
Engine smooth idle, good accelaration, trans not sliping, tire pressure good, plugs new, wires good, air filter new, compression 135psi all clys, no vacuum leaks, no exaust leaks, no codes from the computer, clean throttle body.
Any ideas on what else I could check????

 

your o2 sensor might be getting fouled. Just grab a new Bosch O2 and stick it in. Not to mentioned, stop using crabby brands when it comes maintaining your car. Make sure you're using NGK only spark plugs, and NOT Sh$tfires from bigK.

 

ROFL $hitfires

 

Was going to change the O2 next. $100 for a new one here. Using ND plugs. Can't find NGK.
Anyone know how to install a heated O2????

 

www.nissanpartstore.com

$60 and you only needed one O2

 

Lowest price I could find here is $100. $60 + shipping would be about $80, and sometimes take about a month to get here.

 

Hello, have the same problem like You, but I changed; spark, air filter, automatic oil and the Oxigen sensor and did´t change in my consume.
If You have a solution , please let me Know.

Tks

 

i'd also check the fuel filter....and go easy on the throttle! don't be lead footed

 

what's his driving pattern like? has it recently changed becasue even a little more traffic or city driving can make a big difference.

have you done some gas cleaner and an oil change? probably won't help, but I usually do the cheap stuff before the $100 02 sensor (man, I didn't think prices in hawaii would be that expensive).

 

$59 shipped from www.thepartsbin.com

Oxygen Sensor
Qty: 1
Price: $59.00
Part #: C5010-58305
Sub Total: 59
Shipping: 0.00
Tax: 0
Core: 0
Total: 59

 

i only get 16-17 mpg . how often does the o2 sensor need to be replaced? I think I still have the original one in the max.

 

every 100k according to bosch