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Discussion Starter · #1 ·
1995 Chevy Sub 454 TBI surges and dies after start up. have to hold pedal down to idle then it will idle at 1000 rpm after a few minutes, NOT necessarily when warmed up.
It set code for IAC so it is new .....same issue.

- 105,000 miles
- new NGK UR plugs, cap, rotor, wires
- new IAC valve
-new Speed control valve
-pulled Throttle body, cleaned and replaced gasket.

It is a WORSE gas hog now that it runs like poo....
 

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sounds like the computer is trying to give a goofy fuel/air mix because it thinks its real cold or something.. it could be a bunch of things though. did it just start doing it as soon as you put a tune up in it?
 

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Discussion Starter · #3 ·
been doing this for awhile...
I replaced a vacuum line yesterday and it finally stays running but still surges...
with the air cleaner off i was watching the fuel delivery from the injectors and it was pulsing .....
That is why it surges... NOW to find out why it is pulsing like that.... ANYONE know when this ECU goes into closed loop???
I will do filter and pull the injectors next and clean them....

what a pain...

Thanks!!
Steve
 

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maybe the best thing to do would be to get a code reader and plug it in and see what codes you have.. the injectors should pulse when your cranking it over to start but once it starts its not supposed to do that it should be a steady flow
if the computers in closed loop you could just reboot it but when my old truck went into closed loop it just raised the idle way up but it stayed running
 

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one more thing, I once owned a '93 s10 and it had a 4.3L vortec CPI.. it did the same thing it was like it was hunting for the right idle.. but it was running real rich .. I never found the problem though because I seized the motor a few weeks later.

maybe your fuel pump or filter is causing restriction what does it do when you step on it
 
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