Fuel Mileage Problems ~ 1994 4Runner

[demonsss]

Hi everyone,

I live in Las Vegas, NV and 2 weeks ago I bought a 1994 4runner (3.0, auto, 4x4) from a private party down in Phoenix, AZ. I thought it was a great purchase being completely stock (it was always a wife's vehicle) and had only 145,000 miles on it. Aesthetically it was taken very good care of however now since I've owned it I'm questioning the general maintenance that was done on it. I've had one hell of a week with it . . .

Last Wednesday my battery died on me (living in the desert I'm used to this so no big deal, I got a new one)

Driving the truck back from Phoenix and for my next 2 gas fill ups in Las Vegas I was averaging 17.5mpg (calculated by trip odometer and amount of gas needed to fill the tank and doing the math).

Around Tuesday/Wednesday (started before the dead battery) I noticed the needle on the fuel gauge dropping very quickly. Fuel mileage dropped to 10ish mpg. No smoke of any color coming from exhaust and no puddles under the truck. Next tank of gas dropped all the way to 7mpg.

So Saturday while I was working my boyfriend started to look into it and found the distributor very loose under the hood and the timing WAY off, he said it was so far off he couldn't even measure it. He adjusted the timing and tightened down the distributor. We also changed the fuel filter just because it was never done and thought might as well. After looking over the entire fuel system there is still no visible sign of leaks.

Monday rolls around and I had a tire blow out on the freeway. It didn't damage the truck (or me) thankfully but definitely added to my bad luck streak. I guess it should be noted that I checked all tire pressures and tires when I replaced the battery and though they were aged and had some uneven wear I assumed they had about another 6-8 months on them before being in the red. I replaced the old tires (honestly don't even remember what brand/type they were but they were more typical small SUV passenger tires) with BF Goodrich All Terrains.

Last night my AC started to go out, I'm hoping just low on frion, so this morning I am at Firestone getting an alignment because of the uneven tire wear and the AC recharged and this is where I'm writing this post.

After replacing all of the above, this morning before Firestone I went to fill my truck up again (we filled it immediately after the distributor/timing/fuel filter fix so this tank of gas is completely used after that fix and a Chevron Techron fuel injector cleaner additive was added to the tank) and this tank averaged 12.5mpg. Still no visible leaks, no puddles, and no smoke coming from the exhaust.

Can someone please help offer some advice as to which direction I need to look toward next? I'm thinking maybe spark plugs?

I'm definitely not fluent in vehicle mechanics but I do have some basic knowledge of how it all works. I blame me getting my civil engineering degree instead of mechanical engineering, too bad I didn't pay more attention in thermodynamics.

Excuse the rambling, just bored waiting from my alignment to be finished. Any advice is greatly appreciated!

 

[rickc5]

First, it's amazing how much can need to be done to older used cars once I/you/we buy them (my stories are just like yours). And you're right: it seems that the previous owner of your 4Runner neglected a bunch of maintenance.

Moving forward; Yes, spark plugs, plug wires, distributor cap and rotor should all be changed. Then check/reset timing again. Also replace the engine air filter (I bet it's filthy). There's also a possibility that your fuel injection system needs some attention. I'm not a FI expert, so I can't offer any advice as to what might be needed. This is all minor/inexpensive stuff that won't break the bank.

Lastly, I wonder if the timing belt has ever been replaced? At 145K, this may be overdue. This isn't a minor repair. Any receipts for previous work come with the truck?

 

[toyotafan]

So the battery and tire are just from age. You got them fixed and move on from there.

The terrible MPG is caused from inefficient combustion and/or poor distribution of chemical energy to mechanical energy.

Yes, do a proper fuel system cleaning and a full tune-up. Check to see what condition everything is in when it's being changed ... that is, get photos of the spark plugs when they're changed to see how fouled they are. Look at the connectors on the plug wires to see what they look like.

Do it all at once or one at a time and check your mpg when you can.

Also, I had a vehicle once with sticking brakes that once I fixed them my MPG shot up like 20% instantly because they were constantly grabbing. Just one of those things that you never know until you look at them.

 

[tibadoe]

All the info above is good info. Something else to consider: Are you getting your gas from the same station? Just curious if the "brand gas" itself could be factoring in the poor mileage. Always good to get your fuel from high volume stations. Keep us posted on your results.

 

[BuffaloBill]

Hi everyone,

Hi everyone,

I live in Las Vegas, NV and 2 weeks ago I bought a 1994 4runner (3.0, auto, 4x4) from a private party down in Phoenix, AZ. I thought it was a great purchase being completely stock (it was always a wife's vehicle) and had only 145,000 miles on it. Aesthetically it was taken very good care of however now since I've owned it I'm questioning the general maintenance that was done on it. I've had one hell of a week with it . . .

Last Wednesday my battery died on me (living in the desert I'm used to this so no big deal, I got a new one)

Driving the truck back from Phoenix and for my next 2 gas fill ups in Las Vegas I was averaging 17.5mpg (calculated by trip odometer and amount of gas needed to fill the tank and doing the math).

Around Tuesday/Wednesday (started before the dead battery) I noticed the needle on the fuel gauge dropping very quickly. Fuel mileage dropped to 10ish mpg. No smoke of any color coming from exhaust and no puddles under the truck. Next tank of gas dropped all the way to 7mpg.

So Saturday while I was working my boyfriend started to look into it and found the distributor very loose under the hood and the timing WAY off, he said it was so far off he couldn't even measure it. He adjusted the timing and tightened down the distributor. We also changed the fuel filter just because it was never done and thought might as well. After looking over the entire fuel system there is still no visible sign of leaks.

Monday rolls around and I had a tire blow out on the freeway. It didn't damage the truck (or me) thankfully but definitely added to my bad luck streak. I guess it should be noted that I checked all tire pressures and tires when I replaced the battery and though they were aged and had some uneven wear I assumed they had about another 6-8 months on them before being in the red. I replaced the old tires (honestly don't even remember what brand/type they were but they were more typical small SUV passenger tires) with BF Goodrich All Terrains.

Last night my AC started to go out, I'm hoping just low on frion, so this morning I am at Firestone getting an alignment because of the uneven tire wear and the AC recharged and this is where I'm writing this post.

After replacing all of the above, this morning before Firestone I went to fill my truck up again (we filled it immediately after the distributor/timing/fuel filter fix so this tank of gas is completely used after that fix and a Chevron Techron fuel injector cleaner additive was added to the tank) and this tank averaged 12.5mpg. Still no visible leaks, no puddles, and no smoke coming from the exhaust.

Can someone please help offer some advice as to which direction I need to look toward next? I'm thinking maybe spark plugs?

I'm definitely not fluent in vehicle mechanics but I do have some basic knowledge of how it all works. I blame me getting my civil engineering degree instead of mechanical engineering, too bad I didn't pay more attention in thermodynamics.

Excuse the rambling, just bored waiting from my alignment to be finished. Any advice is greatly appreciated!

Emergency brake on? Stop riding the brakes?
I live in Las Vegas, NV and 2 weeks ago I bought a 1994 4runner (3.0, auto, 4x4) from a private party down in Phoenix, AZ. I thought it was a great purchase being completely stock (it was always a wife's vehicle) and had only 145,000 miles on it. Aesthetically it was taken very good care of however now since I've owned it I'm questioning the general maintenance that was done on it. I've had one hell of a week with it . . .

Last Wednesday my battery died on me (living in the desert I'm used to this so no big deal, I got a new one)

Driving the truck back from Phoenix and for my next 2 gas fill ups in Las Vegas I was averaging 17.5mpg (calculated by trip odometer and amount of gas needed to fill the tank and doing the math).

Around Tuesday/Wednesday (started before the dead battery) I noticed the needle on the fuel gauge dropping very quickly. Fuel mileage dropped to 10ish mpg. No smoke of any color coming from exhaust and no puddles under the truck. Next tank of gas dropped all the way to 7mpg.

So Saturday while I was working my boyfriend started to look into it and found the distributor very loose under the hood and the timing WAY off, he said it was so far off he couldn't even measure it. He adjusted the timing and tightened down the distributor. We also changed the fuel filter just because it was never done and thought might as well. After looking over the entire fuel system there is still no visible sign of leaks.

Monday rolls around and I had a tire blow out on the freeway. It didn't damage the truck (or me) thankfully but definitely added to my bad luck streak. I guess it should be noted that I checked all tire pressures and tires when I replaced the battery and though they were aged and had some uneven wear I assumed they had about another 6-8 months on them before being in the red. I replaced the old tires (honestly don't even remember what brand/type they were but they were more typical small SUV passenger tires) with BF Goodrich All Terrains.

Last night my AC started to go out, I'm hoping just low on frion, so this morning I am at Firestone getting an alignment because of the uneven tire wear and the AC recharged and this is where I'm writing this post.

After replacing all of the above, this morning before Firestone I went to fill my truck up again (we filled it immediately after the distributor/timing/fuel filter fix so this tank of gas is completely used after that fix and a Chevron Techron fuel injector cleaner additive was added to the tank) and this tank averaged 12.5mpg. Still no visible leaks, no puddles, and no smoke coming from the exhaust.

Can someone please help offer some advice as to which direction I need to look toward next? I'm thinking maybe spark plugs?

I'm definitely not fluent in vehicle mechanics but I do have some basic knowledge of how it all works. I blame me getting my civil engineering degree instead of mechanical engineering, too bad I didn't pay more attention in thermodynamics.

Excuse the rambling, just bored waiting from my alignment to be finished. Any advice is greatly appreciated!

 

[jazz]

I had same 4Runner and fuel mileage was 20mpg(imperial gallons) at 60mph or 14mpg(imperial gallons) towing my ship
Properly tuned should fix it. Air filters are critical. You can get history of vehicle with VIN through Toyota to see if warrantied head gasket was done.