What are the general steps to take when you have a vehicle that will run with the gas pressed but sputters and dies on its own?

So far I have replaced all the vacuum hoses with silicon hoses and plugged the egr to see if that would help. Also I have tried the carb clean vacuum leak trick. Nothing yet.

I want to try to pressurize the intake system to see if I can hear any hissing.

Is there anything else I can try?
Thanks in advance.

 

im having the same problem... after doing my headgaskets and putting everything back together it still wouldnt start up smoothly... i lost count on how many times i kept taking things back off and putting them on again and again only to find myself stuck with the same problem... it'll start up but i keep having to press the gas pedal continuosly otherwise it'll just die out... next option for me is to clean out the upper intake manifold... im guessing a clog might be the problem...

 

My oil dipstick was leaking air. Your Aux Air Valve could be malfunctioning. I thought I would pressurize the intake/plenum too a few months ago. I could never get a good seal on the throttle hole. I bought a big cork that fit the throttle but by then I fixed the problem. Eventually I adjusted the valves they were too tight, would not idle at 750 until after.

Your symptoms may be the fuel pump sw in the AFM. or the IDL on the TPS.

 

I went through some more stuff today.
Did a check on the AFM and it was good
Checked the dashpot to make sure it was closed
Made sure the passages in the throttle body were clear
Checked the fuel pump as per Roger Brown
Removed the cold start injector and plugged hole to see if it was leaking fuel

Everything was good and yielded no results.
Tomorrow I will get my hands on some feeler gauges to recheck the valve clearances and reset the tps.
I will also check the oil dipstick(crazy yours was leaking!) and the aux air valve.

Thanks for the suggestions and keep em coming!

 

The reason I thought TPS is because it is one of the only things that makes decisions based on throttle positions. A flaky AFM fuel switch might cause the fuel pump to flicker on and off but I don't think thats your prob. Tight valves caused missing at idle and speed. I can't believe I passed smog with my valves like that but I had just changed the engine oil and that made me pass eventhough it was missing.

What I did for the dip stick was to put some shrink tube on it and heated it up, worked great.

 

Well I had some trouble getting back in the garage this week but today I finally dove into the valves with the feeler guages and they were just about all to tight. After some careful corrections the truck now idles!!!

It's still a little rough so I am going to make sure the tps, the timming, and any other adjustments I can think of are all good.

Thank everyone for their suggestions!!!

 

Glad to hear it now idles!