CUBERA

I know it's sad and im mad. :cry:

I've done all this so far- Clean entire throttle body, clean idle air control valve, clean maf sensor w/ contact cleaner, techron additive.

Spark plugs, timing belt were all changed at dealer 10months ago.

Truck runs strong and idles smooth with no shakes but rpm's seem very low like 550-600 with air off. 750-800 with air on.
It has stalled with air on and with it off giving a little quick shake stumble and stall, but ive came to the conclusion that it stalls when it's at a 1/4 tank of fuel or little less. :wtf:

I don't drive it till' the gas light goes on either. I use 87octane all the time.

I hope i can get some good 3.4v6 opinions.

MTL_4runner

Do you have any water built up in the tank?
It would also be good to take a look a fuel pressure when it does this.
Could be that the fuel pump is getting ready to give up.

AgRunner06

That was my first thought after reading his post. I would definitely have the fuel pressure checked with below a quarter of a tank in it.

Good Luck

CUBERA

O.k. thanx fellas.

How do i check the fuel pressure myself, and how do i check for water in the fuel tank or rid the water out?

MTL_4runner

The best way is to drop the tank down when empty and pull the fuel sender, then look inside for water.
If I was that far I would also just go ahead and replace the fuel pump while I was at it.
Fuel pressure needs to be checked by hooking a guage up to the fuel rail...likely a pro mechanic thing only.

You did say you replaced the fuel filter already right?

CUBERA

Yes i did replace the fuel filter like 8months ago.

What rpm's do you automatic trans. guys idle at most of the time when in gear?

MTL_4runner

The idle should be about 650-750 RPM.
Higher or lower than that could be the sign of problems.

cstary

i've got a stock fuel pump i could send you for cheap if you want to try that . . . .

creed

cubuff4runner

If there is water in the tank it would occur most often before you started driving and shaking the tank. (water is denser than gas). If you don't have gauges to check the fuel pressure, many books will give the oz or ml of gas that should be pumped over a specific time period. All you do is unhook you gas line near the engine and put it in a measuring cup. Turn the key for the specified amount of time and see if it pumps the right amount of gas. After doing this you can also let the gas sit for a while and see if there is any layers. This will decide if there is any foreign substance, water, in your gas. This isn't the most accurate method, but it is a start for people with minimal tools and time.

cstary

sounds more like a vacuum leak - try spraying a little WD40 on the vacuum hoses when the engine is running, but COLD (so you don't ignite the WD40 on the hot exhaust manifold). if you have a vacuum leak, you'll get an increase in idle when the WD40 hits it. BTW - have a fire extinguisher nearby in case of freak accidents.

creed

MTL_4runner

Carb cleaner is equally as effective but just as flammable.
A vaccum leak usually makes it idle higher.....but you never know....worth a shot!