Hi everyone, I've got a 1986 pickup 22r 5 speed 4x4. I've been getting terrible gas mileage lately. 13.8mpg to be exact. I have checked aap; it's good. Replaced plugs, wires, cap, and rotor. Still 13.8. Replaced float on carb and adjusted. Adjusted valve Clearance and checked timing with vacuum plugged. Set at 0 degrees. My new plugs with just 100 miles on them are already fouled. What do ya'll think? Choke? How would I check the choke? Also I have an exhaust leak on the air injection tube. Gasket should be here any day. Not sure if that would be the problem? Oh and does anyone think it could just be my driving habits? I use it primarily for work and it is only 4 miles from my house. Obviously such short trips decrease mileage but... 13.8?!

 

Timed at 0 degrees doesn't sound right.
Yes driving habits have the biggest effect on a vehicles mpg.
Is this a sudden drop in mileage? Just buy the truck?

 

Everywhere I've read I have heard to set at o degrees with vacuum advance plugged then it will be at 8-12 degrees when it's connected. I've had the truck for almost 2 years now. Second owner. Bought it after it sat for a couple years. Used to get 19mpg on 31s. Now I get 13.8. It's been like this for a while. But I had not changed anything on the vehicle. It just happened out of no where. I'm going on a vacation this weekend. Driving from Phoenix to flagstaff. Last time I went I got 18mpg. I'll check it when I go up this time. I was just hoping to fix the milage before taking a 300 mile trip. I'll be loaded with 2 dirt bikes and tons of camping gear and gas so not expecting anything crazy but I'd like at least 17.

 

Also, intermittently it is extremely hard to start. It's a mixture of cranking and mashing the gas pedal. Other times however it starts right up. When it is hard to start, even if it turns over, it will stumble unless I pump the gas

 

Hopefully you already found the culprit but you mentioned it has sat for a few years. Maybe you have some old gas thats been ran through. Have you tried flushing fuel lines, etc. Yet? I have mixed emotions towards fuel additives but maybe something as simple as that would help you out. Let us know!

 

It sat for a few years and I have been driving it for the past year and a half after that. When I first got it, it was getting decent milage but it's gone way downhill since. Have yet to find the culpritt. Recorded 13.4 mpg heading to flagstaff and 21mpg from flagstaff to phoenix

 

I suspect carburetor malfunctions based on information given.

Spark plugs fouling prematurely indicate a rich mixture/excessive oil consumption/Ignition system poor performance.

Verify proper operation of carburetor components.
Fuel contaminations..?

Fuel filter..?

Air intake restrictions..? Air filter dirty..?

Air intake/vacuum leaks..?

Even though Toyota spec is to have the base ignition timing at 0 degrees I usually set alot of stock 22Rs at around 5-10 degrees BTDC. With worn engine parts and engine management parts deterating advancing the timing is necessary on a lot of high mileage engines.

 

Just how are your plugs fouling ??

Did you get the correct plugs??

Are they gaped correct??

Need to go to a hotter plug??

The 5 mile trips are a killer that mileage is about what I get perhaps mine is worse .

I drive very slow being a old person

I never really checked.

 

I would very well attribute my driving habits to my fuel mileage. But the fouling of the plugs is what throws me for a loop.
It's also become harder to start. Used to start after a second of cranking. Now it takes a good 5, sometimes 10 seconds of cranking and pumping the gas.

I'm sure I picked up the right plugs (I look up part numbers before going into the parts store. You can never trust the counter guys.) And I did gap them.

I'm not sure if I maybe need a carb rebuild. I've been tossing around the idea of putting in a weber but I've heard so many mixed reviews on it and I'm not so clear on the legality emissions wise here in az.

 

http://www.aa1car.com/library/spark_plug_fouling.htm

This may be a good read for you.