Nissan Repair: 1986 nissan d21 fuel mileage, nissan d21, fuel mileage

Question
QUESTION: Hello sir,

I am having a problem with the city gas mileage on my old old Nissan truck. My mileage is about 25 mpg on the highway which is great but my mileage in the city is only about 12. The fuel and air filters are new as well as the plugs and wires and also the PCV is new. I just have no idea what is causing this mileage problem? Could it be the EGR?

Thank you!

ANSWER: Hi Eric -

Is your vehicle manual or automatic transmission? What is the engine size?

let me know -
thanks and aloha
calvin


---------- FOLLOW-UP ----------

QUESTION: Manual, 2.4L 4 cylinder

ANSWER: Hi Eric -

What immediately comes to mind is your clutch. Have you checked it for slipping?

calvin

---------- FOLLOW-UP ----------

QUESTION: What can I do to check for slipping?

Answer
Hi Eric -

get your car up to about 25 miles an hour. Put it in 4th gear, and while pressing the accelerator pedal, slowly depress the clutch pedal with your other foot. If the idle RPM rises as soon as you start dperessing the pedal, then the clutch is slipping.

One side note, try pulling out a spark plug and see if the car is running rich. If it is the plug electrode will be jet black. Normal color is a light brown.

Hope this helps -
aloha
calvin