mudman6060

So no one at all knows what in the heck is wrong with my truck. I have an 85 sr5 pickup xtra cab 4x4 with and 22RE 5 apeed. What the truck is doing is.....when you first try and start it...it won't start. After a few tries it'll finally start and idle just fine....no knocks or rough idling. BUT....when you push the throttle quick, instead of reving up...it just bout dies (goes down to round 100 rpms or so) or it cuts off. BUT...if you rev it up SLOWLY it revs up just fine. I've replaced the throttle position sensor and all the vaccum lines I could fine. If anyone has any idea at all on what you think it might be or you know of any way to fix this please let me know. thanks

mudman6060

oh and I've also replaced the fuel pump, fuel filter, and main relay

Team420

got a plugged cat or muffler? Disconnect them, and try again....If same problem...u ruled it out.

mudman6060

right now it's straight headers....no cat or nothin :/ thanks though

mudman6060

seriously...if anyone's got any ideas at all throw em out there....PLEASE lol

Team420

Spark? How are your plug wires, dizzy cap, and rotor? Coil & Igniter? Thats the next place I'd start looking.

Lumpy

What about the AFM??? Is the flapper stuck?

ozziesironmanoffroad

hows the tps? mine would do the same thing til i replaced the tps. also check the iac

mudman6060

team420i've replaced the plugs wires, ect. haven't checked anything with the coil or nothin so i'll have to do that.

lumpy-the flapper is not stuck on the air flow meter (figured it had somethin to do with the afm so i took it off and everything looked fine with it. is there anything else i can do to check that the afm is workin properly???

ozzies- if yer talkin bout the throttle position sensor i just replaced that...all that did was correct the idle. where exactly is is idle air control valve?? i THINK it's right under the throttle body but idk???

THANKS

ozziesironmanoffroad

pretty sure thats where it is....

mudman6060

Is this the iac valve???

mudman6060

also....does anyone know what these 2 things are??? i'm thinkin the one that's got the lil white screw on top that's connected to the intake manifold has somethin to do with some vacuum adjustment...anyone know???

Lumpy

Well I think the white screw thingy is for the AC idle up...If i'm not mistaken.

mudman6060

well if that's so it won't bother nothin...i have no ac at all lol

and i figured out what the other thing is (but Correct me if i'm wrong)...it's an EGR vacuum modulator....think it has somethin to do with makin sure the engine burns all the fuel or somthin like that.

1989toy4wd

Get a haynes manual, there is a way to diagnose the VAF...also check your alternator, believe it or not mine did this once too and the alternator was going out...it would supply enough power at idle but not enough at higher RPMS.

I think its your VAF though!

4Crawler

iTrader: (3)

Try the fuel pump test jumper:
- http://www.4crawler.com/4x4/CheapTri...shtml#FuelPump

And check carefully for any cracks in the rubber sections of the air intake, between the AFM and the throttle body. That will show the same symptoms.

mudman6060

1989toy4wd-well like i said...the truck starts spittin and sputterin and startin to die if i tap the gas quick and hard. if i ease on the gas it'll rev up to 5000 just fine. it also does it if i'm drivin....i think it's when i'm tryin to accelerate and i'm pushin the gas down harder. it's almost like it's actin like it's confused.

4crawler- the fuel pump is workin fine...when i replaced it we disconnected the lines after the fuel filter and turned the key to on and gas just poured out.

4Crawler

iTrader: (3)

But do you know if the pump is working when you mash the gas pedal? The test jumper will ensure power to the pump at all times. If that helps, then check your Air Flow Meter, might be a dropout in the Fc circuit:
- http://www.4crawler.com/4x4/CheapTricks/AFM/index.shtml

And check the Throttle Position Sensor:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

mudman6060

thanks for those links...my buddy's got an ohm meter....so we'll try it and see what we can find out

mudman60

well my buddy still hasn't brought his ohm meter from work. BUT...now my truck won't even start (well it will but you have to let it sit for a lil bit then it'll start then just die after bout a second)...but it will start and run for a sec off of throttle body cleaner. I think what it really might've been all along was we never did clean out the gas tank when we replaced the fuel pump n all. SO...does anyone know good way to clean out a gas tank without buyin a new one??????????