I have a 350 LT1 FI. It has been boggin down and having glass packs on it the exhaust sounds like a 2 cycle/lawnmower. I replaced the plugs, plug wires, fuel filter, and the cap is pretty new.....Anyone have any ideas???? In first gear it will run fine, and in fourth (last gear) it runs fine but in between that it bogs down and sounds like ****

 

What car is it in?Sounds likemaybe a vacuum leak (intake). SES Light, Codes?

 

My first check would be to check fuel pressure and volume. It is very critical on a GM. Just a few pounds short and it will run crappy or not at all. I cannot remember what the spec is for the 350s, but I think it is upwards to 55 psi, someone correct me if I am wrong, and I have notworked on one for a few years. Check volume too. It should fill at least half or more of a quart size jar in ten seconds. I know you said you changed the filter, but the pumps get weak on GMs, that is just what they do. Are you feeling a misfire, or more like a lack of power?

 

Sorry, I think the Vortec 350sare like 55psi. I believe you are looking to be around 45psi.Let me have some more info if you could.

 

May need to clean your injectors.

 

1. Glass packs suck

2. How long have you had them cause they can collapse on their selves. Getting hit or getting too hot and they turn you exhuast into a drain with women hair.

 

i dont think its a vacum leak that would be bouncing rpms.... may be injectors...

 

Pimpin, what kind of car, more specificly what year, and what mods are done to it. I know a lil something about these engines, will gladly try and help ya get it running again. For what its worth i'm also an auto tech, fill me in .........

 

gimme year make model and i can look any spec up on alldata for ya just PM me, but it sounds like fuel pressure or clogged injectors to me too

 

Autozone will read your codes (if any) to help with diagnostics.