Ok, I have read reams of other posts about this problem and none are
exactly the same so here goes I hope someone one here can help!!
Vechicle:
1997 GMC Sierra Fullsize ext cab
4.3L motor 120k mi   5spd
Problem:
When I am under partial throttle between 2k-3k rpm all cylinders
misfire sometimes flashing the SES light. If I step on the gas (WOT)
then it seems to clear up.
What I have done:
changed plugs to Champion truck plugs then to AC Delco Platinum per
Mechanic recommendation
changed wires to Bosch
changed cap and rotor
changed coil
changed ICM
changed fuel filter
I also took it to a mechanic to have the code analyzed it came back as
a Multiple Cylinder misfire, while every cylinder being affected. Some
were 11k times from were 8k times. He looked at the "captured" data and
didn't see anything out of the ordinary.
The plugs are gaped correctly and look fine when I take them out.
Unfortunately I don't have a garage I can work in and Ohio winters are
no fun to wrench, So far I have done everything I can think of and
don't mind spend the time or money if I know it's going to fix it.
A few questions:
As anyone seen this exact problem?
What order should I test these in:
compression
fuel pressure
fuel injector poppets
computer
what else...? A friend of mine owns a salvage yard so I can get parts
pretty easily
Please help and thanks in advance!
-DC