Hey guys i have a 305tbi engine. Runs very good for what it is. But lately when i start it up it will want to die? Ill give it gas and it will keep running but would like to get it fixed! I have never changed the fuel filter? wheres that located and it should only be a few bucks right? thanks kevin

I don't believe the filter is your problem, but it's under the floorpan, below the back seat on the driver's side. The dying should be throwing a code. Start there.

It throws a code every once in awhile when im driving but i can never keep it on for auto zone or someone car figure it out. Bc everytime i shut it off and start it up it gose away for awhile? But will never come on jus by turning the key.
kevin

Does physically adjusting the linkage at the TB to increase the idle speed seem to help? I think we can rule out vacuum leaks and a bad TPS, as well as a bad O2 sensor.

i already bumbed the idel up.
kevin

even though you ses light turns off, the codes are still stored in the ecu. You need to cross the top right 2 terminals on your 16 pin ADL port. it should blink 1 steady blink then 2 fast blinks showing the ecu check is good. then it will blink slowly for the first number, fast for the second number.
12- blink, pause blink blink
example; 24- blink pause blink, pause blink blink blink blink

I have this same issue going on. It only happens sometimes and usually on a cold start. It will start and then immediately die. I start up again and press the pedal a little and it revs a little rough for a few seconds and then it's smooth and runs well after that. Odd.

same here, after sitting, especially <40F outside, for longer than a day or so, it will turn, fire, stumble to catch, and die promptly. then, a second later, try to restart and it immediately fires, catches randomly, and idles like a funny car would, with a window shaking cam (no knocking, just missing, like that old massey ferguson first starting under full choke)--apply part throttle, and it eventually smooths out--but there seems to be a lack of the typical warm up "step-down" idle of the cold motor after than, and instead, goes direclty to 300 rpms above normal op temp idle (875/900 or so) and holds steady. i've replaced every sensor on the tbi (for age purposes), reset, and cleaned the iac passages as well. helped, but it randomly does it.

here is where my flow chart begins ... remove throttle body from intake to inspect passages of iac valve see the pic below for reference (long passages off 2" throttle bores/blades); monitor injectors for bleed down when left parked, and system pressurized (flooding intake, too much fuel at start, failed fpr, o-rings in the injectors); run winaldl and see if its lean or rich...wonder if I would need a heated o2 sensor to get results that early at start/closed loop, or a wb o2 sensor??
anyway, im pretty sure its getting too much fuel. regardless, change the fuel filter, tune her up so you have a baseline to start with, and go from there. i've also read somewhere that a crack in some portion of the distributor causes this funny starting too (insulator maybe?? dunno, seems like I saw a pic from a senior member and it was about 3" down the shaft). i've searched for hours reading about cold starting problems... those are the routes i'm headed. also, fwiw, there is a cold start injector (9th injector) on some models-be leary of that. and, just to do it, i'll likely take my intake off to clean the egr passages.
changing the idle is something I am against... a prime example of leaving your baseline, and masking the issue (neglect likely, hehe!) there is a screw hidden, you have to drill the cap out--i wouldnt dare touch the throttle linkage, as it directly affects the tv cable for the transmission (i'm guessing anyway) the pintle and stepper motor in the iacv should get 'er done well enough you shouldnt need idle adjustments--i've seen my car idle like a baby at 525rpm

finally, as it's almost 4:20am, i've read that the coolant temperature sensor will drastically affect engine operation, and this was the solution in some cold start/idle problems.

fuel, air, spark!!!! compression is good sometimes too. half a plugged iac passage will make her talk funny

I wanted to ask everyone, when starting, a good healthy start, does it sound like right before the engine becomes self-sustained, and you're instantly letting off the key, does the engine seem to pause for a half-second, almost take a gasp, and them begin to orchestrate and bump along?? usually, when it fails to start with the above mentioned symptoms, it takes that gasp...after firing, but never catches (promptly dying part). it doesnt do this when warm, or normal... its very fluid and instantaneous. strange stuff, these chevy animals.....

Hey guys i'm having the same issue with my car at the moment. Its not a big deal more anoying to the neigbors at 4am when i leave for work and rev the engine to about 5k with a 3 inch flowmaster and cat delete. Gonna change fuel fillter in the morning and did a seafoam treatment today. Yet to see how much that helped.

I too have the same problem. With mine it used to do it hot or cold. It will rev up then rev down and die. Started it back up and keep the revs high and it would eventually "learn" itself again and idle good. but if I turn it off and start it back up again it would do it again. I work at an auto shop and the techs there figured out it was a bad idle air control valve and fuel pressure regulator.

They replaced those and now it only does it when it is cold so I am leaning toward a coolant temp sensor. Doesn't help that I have a mis-fire in cylinder 4 either. I have also been told that it could be because of a bad ECM. Any ideas?

well the seafoam didn't help me any but i may look into the coolant sensor. i used to have an s 10 4 cyl. that did this but only when the motor was running and it got hot.

yeah I seafoamed mine too when i first got it and it didn't do much good. I am up for any ideas about what the problem is.