i got a 305 tbi in a 88 silverado
single cab standard box, 4 speed
700r4, when i start it it will idel perfect
but when you push the gas it sputters
and runs really rough, but if you let it warm up
it gets better and better till it eventually goes
away, does anyone know what this porblem is????

 

sounds like a sensor problem in your Throttle Body....just a quick piece of advice....just save up and go buy a new throttle body....the rebuild klits for the throttle body are crap, infact the holley throttle body you can get on ebay for a cheaper price, and they work great. my 83 cj-7 has a 350 tbi swap, and it ran like crap after 3 rebuild on the TB, i then went with the Holley TBI and it was GREAT!

 

i have 2 morethrottlebodys off of 4.3 v6's that i have scrapped,
everything is the same except the injectorsdo you think i should swap some stuff, like the throttle position sensor or map sensor

 

Probably moisture in the cap from crud built up in it..................On cold start up they run ignorant,but the engine heat dries em out!

 

i know i bought a new cap and rotor tryed all that, could it be the timing advance sticking for some reason???

 

i also got 8 new plugs, i tryed 8 different plug wires, new air filter
i dont get it ya kno, it idles like brand new but when u stomp the petal
it just misses like crazy, i checked the compressionall arround150psi
on all 8 cylinders

 

it ran fine first when i bought it then all of a sudden it was running ****ty
does anyone kno wats goin on or at least heard of this kinda problem b4?

 

I still say its ignition if it idles fine....

Cheap cap..
cracked plug...

In RARE cases,maybe a bad crank sensor...Any check-engine lite??

 

yeah man after like 2-3 mins the check engine light comes on

 

your right it more than likely is ignition,
but i'm not sure about moisture, tomoro ill
pop off the cap and dry it out with a rag and
some wd-40 and maybe change the ignition
module orw/e it is called under the advance