86 corvette running rough

[chrisfrom nj]

im working on my uncles 86 corvette i did the complete tune up plugs wires cap rotor gas filter oil filter the car has 62,000 miles on it it was sitting for a long time when you start it up it takes a while to fire up then it runs rough then it smooths itself out then when you give it gas it seems like it misses all the plugs that i took out all looked the same the engine was running the same im confused it seems like a fuel problem could it be old gass causeing this or bad injectors please help

[chrisfrom nj]

its a 350 tpi with aluminum heads

[NJSPEEDER]

throw in a can of dry gas and see if that clears it up. if it does, you know it had bad gas in it.
is there a servie engine light or anything?

[chrisfrom nj]

Originally Posted by NJSPEEDER

throw in a can of dry gas and see if that clears it up. if it does, you know it had bad gas in it.
is there a servie engine light or anything?

i threw in a can of dry gas it still does the same the car was sitting for about 3 or 4 years

[chrisfrom nj]

Originally Posted by chrisfrom nj

i threw in a can of dry gas it still does the same the car was sitting for about 3 or 4 years

no check engine light on it runs rough and then runs normal then it runs rough

[BonzoHansen]

Originally Posted by chrisfrom nj

...the car was sitting for about 3 or 4 years

That adds to the fun. How much old gas is in it, did you add any new gas?

[chrisfrom nj]

i didnt add new gas the car has a full tank

[The Fixer]

Try siphoning some of the old gas out of the tank and adding fresh gas, then change the fuel filter and run a can of injector cleaner through it. That might clear it up.

[V]

autozone sells a small plastic siphon pump and plastic hose kit for .99 cents. it actually worked pretty good. just dont expect to use it more than once or twice.

[chrisfrom nj]

thanks im going to siphon as much gas as i could out and put fresh gas in allso i just changed the gas filter about a week ago the car hasnt been running all that much should i change the gas fiter again

[JSPERFORMANCE]

check the fuel pressure, it could be a weak/funky pump as well

[chrisfrom nj]

i drained the gas fresh gas put a bottle of chevron fuel injector cleaner and it idles good and bogges when you bring the rpm up then at 2500 rpm it runs good what should the fuel pressure be

[chrisfrom nj]

what should the stock fuel pressure be set at

[JSPERFORMANCE]

43.5psi total at w.o.t.

[chrisfrom nj]

if its not fuel pressure what else can it be

[Savage_Messiah]

vacuum? ignition?

[JSPERFORMANCE]

it is un limited, you just need to test all systems and repair or replace as recissary.

[chrisfrom nj]

thanks im getting a fuel gauge tomorrow to check the fuel pressure

[chrisfrom nj]

the fuel pressure was 34 even at open throttle the gauge didnt move then i blocked off the fuel return hose the car ran better and the pressure went up little by little if i had a good pump the pressure would have came up instantly it took some time for it to come up the pump grindes im going to put a new pump in it tomorrow hopefully it will solve the problem i hope its not the fuel pressure regulator

[chrisfrom nj]

i disconnected the battery i changed the fuel pump and it still runs rough then when the temp is 200 the car runs alot better what can it be

[enRo]

Check for any vaccuum leaks.