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