Matt3203

ok so ive looked around and ive found nothin, so dont say search!

i have a 1994 t100 3.0 4wd 5spd

i been having this really annoying problem with my engine and it seems its not getting enough fuel, it surges back and forth and sometimes it starts to buck pretty bad. and it seems to get alot better when i get gas but then it starts back after a day or sometime less then 4 hours.

i replaced the fuel filter and it fixed the problem for bout a day and then it came back. i have no idea what could be wrong please help

Matt3203

also my engine never warms up anymore! it stay less then 1/10 on the temp guage

BamZipPow

Sounds like yer thermostat is stuck open. Did you pull it and check it out?

Have you drained the gas tank and have it inspected? You could have water in yer tank or something. Did you check out the fuel filter to see what sediment/material was in there? I guess you could pull the fuel pump and sit it in a tank of fresh gas as a check...

You could also have a bad fuel pump...did you do the test on it yet??

Matt3203

i cant find where the t-stat is?

and when i changed the fuel filter did seem to have some rust colour gas in it come to think of it


should i just drain the gas out and flush it with something?
if so what should i flush it with?

BamZipPow

Don't just try to flush the tank...there's a reason why there's rust in there. I'm gonna venture to say the top of the tank might be rusted where the fuel pump seals. Drain and drop the tank to make sure you git it right. Don't do this half-assed...you don't want to revisit this when yer stuck on the side of the road...

The thermostat should be located at the water inlet to the water pump. Only 3 nuts hold the neck in place...make sure you git a new O-ring gasket and new thermostat before you start though.

Matt3203

so drain the tank and drop it and check the fuel pump for rust ?

Matt3203

also little puffs of white smoke comes out of the tail pipe, and it seems to have a rhythm to them

BamZipPow

Well...I gonna say the rust in the tank will have affected the filter on the fuel pump. Most of the time, rust will have affected the lines or the tank (internal or external). If yer gonna inspect and treat the tank fer rust...you might as well do it the right way.

BamZipPow

Are you losing any coolant? You could have blown head gasket as well...do the check fer that, too!

Matt3203

well my oil is pretty clean

Matt3203

so replace the stainer too right? or just replace both stainer and pump?

BamZipPow

Although that is a test fer a major blown head gasket...you could have a small leak. Compression test, cooling system pressure test, cylinder visual check, spark plug visual check would be better indicators. You could probably pull the plugs and see which one is different than the other ones...water will clean that plug really well.

BamZipPow

You won't know until you pull it to see. In some cases, you can clean the pump strainer...but it will all depend on the condition. If yer fuel tank is rusted from the inside...you might look at POR-15's fuel tank sealer.

Matt3203

ok so i should prolly bring it to a good mechanic then so he can check everything out? wouldnt a blown head gasket make the engine run hot? no cold? and the white puffs of smoke go away in bout 30sec after start up.

if i drain the fuel tank is there something i can just pour in the tank to eat the rust off then drain it again?

Matt3203

can i just drain the tank, pour phosphoric acid in it, let it sit for a while then drain and let it dry out and then refill with gas?

Matt3203

can i just suck some gas out and see if any of it have rust in it

no other part of the truck has any rust at all so im skeptical that this is the problem but im willing to check

nikh713

my tank had a big rust hole in it and bits of rust fell into the tank, and got stuck all around the strainer. it would make my truck buck back and forth real bad when accelerating. after replacing the tank with new pump and strainer it fixed my problem. good luck with yours

Matt3203

well i figured it out i had a bad efi relay and a vacuum leak on my intake, pluged the vacuum hose back up and changed the relay and runs like new now

nikh713

was it hard to start when it was cold? or did it always start right up? i'm having a problem starting it up when its cold

Matt3203

yeah it did and it still does i can figure that one out but at least it runs like it suppose to