I have a 355 vortec with stock tbi with 90lb/hr injectors,shorty headers,and stock exhaust,with lt1 cam,and custom chip from tbichips.com, it idels fine but when you open it up as if to pull out into traffic it just cuts out, but if you let off and let the engine catch up it runs.Do you guys have any ideas what might cause this?Thanks in advance

 

Have you checked fuel pressure? Kind of sounds like it could be starving for fuel when you go to open it up. My 305 did something very similar to that. It was the fuel pump.

 

Ill have to get a fuel pressure gauge.

 

So you're saying that with quick throttle stabs it cuts out, but will eventually catch up and do fine even at higher RPM?

 

yes,as long as I back out of it and give it the gas slowly

 

First rule out fuel pressure. You need to check pressure under load, this means taping a gauge to the windshield or something and going out for a drive so you can observe fuel pressure at the moment the problem occurs.

What cam are you running?

I feel pretty confident in saying it's probably the tune. Mail-order chips are a waste of money. Every engine is different and nobody could possibly write a tune that is close on the first, or even the second or third try.

What you're describing sounds exactly like what happens when the engine isn't getting the proper AE (acceleration enrichment). During a rapid change in manifold pressure such as what occurs during a throttle stab, the atomized fuel can drop out of suspension and condense on the manifold walls. AE is like a "pump shot" that adds extra fuel to make up for the fuel that is now stuck to the walls and not reaching the cylinder. Having burned over 400 trial+error chips for my own TBI, I know just how hard this is to get right. Do you notice it any better or worse when the engine is cold?

 

I'm running the f body lt1 .447/.459 lift,I will get a gauge asap,I did find out my pump strainer and attachment was barely hanging on and fell off when I pulled the pump.The strainer and tank are full of rust.Don't know if this is my problem but definitely needs to be fixed.

 

I will be getting a laptop and data logging with winaldl and sending the data to my tuner.I would do this myself but I have no idea what to change or where to start.someone told me that ebl would make it easier but I have no Idea.Thanks for your replies.