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Discussion Starter · #1 ·
Hey guys. I have done some searching and have read a lot but I was hoping you could help me narrow down my problems.

I have a 1995 2wd with a 4.3 tbi. The truck has 168,000 km (105,000 miles). I park in an underground parking garage. I start the truck up in the morning and let it run for approx 3 minutes and it idles fine. i drive for about 5 minutes downhill so i don't have to give it much gas i just cruise down the hill at about 55mph. Last monday I got to the bottom of the hill and as soon as i stopped at the light it sputtered out and stalled. No check engine light just check guages cause I lost oil pressure. I was going to post up about it but it seemed to run fine ever since then. That is until this morning when the same thing happened to me THREE times in a row every time i came to a stop. After that the truck ran fine even while stopped. I should mention that it always starts up again no problem

My other problem is sometimes, but not always, when i start the truck up warm it shakes and sputters and sometimes stalls. This usually happens if i let
her sit for about 20 minutes or more. It sometimes takes 3 or 4 tries to get it running and i have to work the gas brake 2 foot style until i can get out of the parking lot to the main road and get it up to 30mph or so, then it runs fine.

So i have a list of things to check for, i would like to do the work myself but i dont have much experience. I will buy the tools if i dont already have them, i just need to figure out how.

First. There is some sludge built up under the throddle body assembly. I will take a pic later and post it up after work. The injectors spray evenly as far as i can tell.
Bad fuel pump?
Vaccum lines?
Sensor problem?
Leaking fuel lines?
Bad fuel filter? Just replaced it but i used a fram

anything else that could cause this?
I had a major tune up about 5,000 miles ago. Regular oil changes every 3000 miles, autotrans fluid done about 3,500 miles ago

im at work now posting from my iphone. I can come back with more info and pics later on.

Thanks guys
 

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registered loser
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Discussion Starter · #2 ·
I nearly forgot to mention: when it was stalling out this morning the backlit dash and the clock on my radio dimmed out while it was stuttering but lit back up once it stalled cause the key was still in the on position. I was running the headlights and the stock radio but nothing else.

Might help?

I have a relatively new starter, battery, and alternator.

Ignition coil maybe?
 

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No More SS
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My 97 SS does this, but not as extreme. It has never completely shut off at a stop. I was told it sounded like the egr, but I have not checked it out since it doesnt get driven much anyways.
 

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F.ound O.n R.oad D.ead
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my girlfriends saturn did this , it was a loose power wire from the starter to battery.. dont know if thatll help but yeahh
 

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Discussion Starter · #5 ·
hmm... well Saturn is made by the General Malfunction company so there could be a correlation.

j/k that could happen on any make.

I will check that out

for some reason I feel like it should be a fuel issue but I guess it could be anything
 

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F.ound O.n R.oad D.ead
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yeah well the obvious easy way is fuel pressure test before you go searching for loose hoses and wires and spend money that you could otherwise keep. Ive made teh mistake a few times haha
 

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Discussion Starter · #7 ·
According to my repair manual i have to check the fuel pressure along the frame where the fuel filter is attached. I havent seen a schraeder valve along the fuel line in the engine bay so i guess i need to do that and swap the filter out again just incase.

Step one - buy tool
any reccomendations for a better quality filter or is fram ok?
 

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F.ound O.n R.oad D.ead
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i always used the spectre clear filters because
one there cheap
and two i can look and see if there dirty.
My fuel pressure was fine with a year old one and it was dark brown so it definitely did its job.
 

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Discussion Starter · #9 ·
Hey guys, it's been 2 weeks since I posted this. I have driven about 350 miles/550 kms since then. just had a few observations to share.

I don't think that these two problems are directly related and I'm much more worried about the first problem, stalling at red lights, than the second problem with the rough idle. Its been a bit shaky ever since i got it almost a year ago but the stalling thing is new and happens at different times.

It runs great 98% of the time but over the last 14 days it has acted up a few times.

usually if it stalls, its when its about midway between cold and normal driving temperature.

it more frequently (but not only) stalls when my gas tank is below half.

when its threatening to stall it revs low and shakes struggling to stay alive. at this point the electronics lose power but not completely. radio gets quieter, dash lights and clock dim. Im not sure if my headlights dim, wasn't paying attention to those. at this point it either stalls or revs up a lot higher and either stays alive or begins to idle low and then shake and repeat the whole process. the one day it happened at a red light near my house while in drive and when the engine revved up it was almost enough to bump me forwards a bit even with my foot on the brake.

so this has me believing that it is something electrical, ignition coil? a loose ground wire for??? a loose connection? but to what?

I checked the PCV today and it has plenty of suction and it rattles nice. should be ok.

I just got a digital multimeter so I was going to test my O2 sensor and ignition coil(s) when I have some free time. no idea where to start with the o2 though, i can't find any mention of it in my repair manual

like I said before, this is my first vehicle and I don't really know what I'm doing in terms of repair... I have a manual and some time, i can buy whatever tools I don't have, but I don't really know where things are under the hood or how to find them, so i might need some help as I go.

thanks for your help guys
 

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funny my 91 jimmy i bought runs a little rough when you hit the breaks but its sat for 3 years could new plugs and fuel fix this along with a new fuel filter
 

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Discussion Starter · #11 ·
new fuel? yeah 3 year old gas wont run too good :) i think maybe you missed a word there?

my truck sat for a long time before I started driving it. It ran like shit at first but a tune up including new plugs, wires dist cap etc helped big time
 

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Discussion Starter · #12 ·
aha filter. you should know if your fuel filter is clogged. in my experience there is a noticeable difference in the sound and feel of your vehicle. you should be able to tell if this is the problem or not
 

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i havn't even drove it home yet but i bet the gas has congealed a bit inside the filter lines and injectors so it will be getting a new one as well as one hell of a run home to try and move as much fuel through the system and clean it out abit but once i sell my truck it will be getting a tune up plus fuel filter injector cleaner and a octane boost
 

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4=twice the cool of 2!
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Possibly a dry rotted/cracked vaccum line? Mainly check the line going to the vaccum reserve (black ball) and brake booster. Had a few dimes have lines cracked but not broken, and cause them to act up randomly. This would explain the rough idle, and if the line going to the brake booster is broken could cause it to die completely? Just my .02
 

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Check and clean the IAC, reset the PCM after cleaning the valve.

The voltage will drop when the PCM drops the alternator out to reduce engine load to try to keep the engine idling if it is idling too low IIRC.....
 

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Discussion Starter · #16 ·
@4door - I have looked at various vacuum lines and they appear ok but I will check those specific ones... if I can find them :)

@lesterl - where is this IAC you speak of? i have heard it referred to before but I don't recall any reference to it in my manual.

resetting the pcm should be pretty straight forward right? just disconnect the neg batt terminal for over 30 mins. no secret handshake required.
 

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thats what im thinking is the line to the break booster seems to run rough for a secont or two then clears up if im not mistaken the power breaks work so imagine it wont be the brake booster itself would it?
 

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IAC looks like a roll of quarters on the older TBI's sticking straight out with 4 wires on a square plug. Some of the newer engines have a stubby 1/3 roll with a 4 wire plug comming out of the bottom (all 4 wires are in a row - not square plug...)
 

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Discussion Starter · #19 ·
thanks. I think I found it... on the left, under the air filter housing sticking out of the tb
 

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sounds about right..... lettuce know.....
 
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