Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry for the long wait
when it is at idle it has a bad miss ?
and there are NO vacuum leaks ?
how high is the RPM once it starts ?
are there any codes being set ?
did it do this since the engine was rebuilt or it ran after it was rebuilt good for a while ?
are there any vacuum leaks ?
did it do this before the rebuild ?
at 1000 it is running bad correct ?
if so if you unplug one injector are a time will any you unplug NOT make a difference in the idle ?
at idle see if any you unplug do NOT make a difference in the idle
we are looking to see if we have any dead cylinders
if you unplug an injector that the cylinder IS working the idle will get worse
a cylinder NOT working the idle will not change at all
can you see if any cylinders are dead ?
see if it has any dead cylinders first
let me know
ok lets see if any cylinders are dead next
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at idle unplugging the fuel injectors one at a time where there any dead cylinders ?
or all 8 made a difference when unplugged one at a time ?
yes you are correct the spec is 41 - 47 ley ON engine OFF
if it is below that replace the fuel filter if it still below spec the fuel pump is bad
yes low fuel pressure can cause a miss
but we have to find out if it is a specific cylinder misfiring or not
and we need you to unplug each injector like i said to see if there is one or two specific cylinders missing or dead or not
if all 8 you unplug one at a time make a difference in the idle then we know this issue is something that is effecting all 8 cylinders
we need to know this
yes replace it and the fuel filter and see if the pressure gets back to spec then see how the engine runs
the pressure needs to be corrected to spec first
if the fuel pressure is back to spec and still does this then see if there is a specific cylinder or not missing
i have just seen this time and time again of a few cylinders with the valves adjusted too tight causing this kind of issue especially after a rebuild
i just want your car fixed
ok i understand
i assumed it did this only after the rebuild
ok correct that fuel pressure first and see with the pressure back to spec how it starts and runs
with fuel pressure to spec it should start and run good