Ok, I have a 1988 GL10 Full time 4wd EA82 turbo 5-speed. My gas mileage used to average 24-26 mpg and after parking the car while I was out of the country for 18 months I have gotten 15 to 20 mpg over the last 4 tanks of gas. I did put some fuel conditioner in before I parked it and I ran a can of Seafoam through it after starting it back up 2 months ago. I also run the Lucas upper cylinder additive with every tank of gas. My check engine light is not on.

 

I have replaced the following parts along with cleaning the MAF sensor:

Spark plugs, wires, cap, rotor, PCV valve, fuel filter, air filter, gas cap, O2 sensor

 

What else could be affecting my gas mileage?

 

The O2 sensor wiring was cut and spliced by the previous owner, so how important is the shielding on the wire from the computer? The new O2 sensor doesn't appear to have any shielding?

Have you checked the tire pressures? I've found that by the time mine looked noticeably low, on the '89 GL wagon, I'd shaved my mileage from 28 average to 22ish. Oops.

 

You've already replaced everything else I'd have suggested... so I'm not sure what else ???

 

As far as the O2 sensor, I've had a check engine light for that on for two years on the wagon, and it still averages 26 to 29mpg, and 31mpg on the highway. It seems to have jumped about 1mpg when I replaced the rotor and plugs though (the rotor and cap were both noticeably burnt after 50k miles).

Tire pressure is ok... any other ideas?

Have you seafoamed your oil and then changed it?

If not, I would recommend pouring about half a can into the oil and the other

half into the gas tank.

Run it for 5-10 min with the seafoam oil, then drain it and fill with new oil of your

choice. (My brat seems to do best with 10-40w)

Hopefully this helps!

 

Twitch

check the timing maybe it can be advanced a tad to bring the mileage back?

when a car sits that long in wet areas the air filter can get damped- dry -damped -dry on and on

 

well you get the story

opps I should have read your post better

 

I see you did change filter

Ok your not going to believe this check your charging system and battery

 

weak battery = weak spark

 

your battery may be good to start it but not good for the best spark

Car sat for 18 months with fuel in the injectors. Injectors now probably in poor shape.

so what do I need to do to get the fuel injectors cleaned out?

use conklin 4power. run as described on the can. it works!!! the BEST on the market. find a conklin dealer in your aera and ask them to show you a demistration of how well it works.