4.2 Misfire under light load
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03-29-2011, 01:56 PM
Join Date: Mar 2011
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4.2 Misfire under light load
Hi everyone. Looong time reader, first time poster.
I had a lean bank 1 + bank 2 code popping up a couple weeks ago. Found a vacuum leak, (elbow under the throttle body) replaced that but now I have a misfire under load and no codes. Engine idles great, but I put it in gear and bring the rpm up it misses and studders(?) at about 1550RPM.
My truck is a '99, 160K,
So far, I have replaced the plugs with new Motorcraft, replaced fuelfilter, checked fuel pressure (34-40psi), replaced wires with known good ones, cleaned MAF, later replaced with new one, new coilpack, new crank position sensor, new PCV, new harmonic balancer, countless hours trying to find more leaks, checked EGR lines for deposits, scanner shows O2's are working fine, no misfire,
Whats next? What am I missing? I'm at a point where a stick of C4 would be the best way to go. I have read probably every thread ever created on this issue and done and checked everything recommended with no luck. Now I'm turning to you good people for advice and ideas.
Thanks
I had a lean bank 1 + bank 2 code popping up a couple weeks ago. Found a vacuum leak, (elbow under the throttle body) replaced that but now I have a misfire under load and no codes. Engine idles great, but I put it in gear and bring the rpm up it misses and studders(?) at about 1550RPM.
My truck is a '99, 160K,
So far, I have replaced the plugs with new Motorcraft, replaced fuelfilter, checked fuel pressure (34-40psi), replaced wires with known good ones, cleaned MAF, later replaced with new one, new coilpack, new crank position sensor, new PCV, new harmonic balancer, countless hours trying to find more leaks, checked EGR lines for deposits, scanner shows O2's are working fine, no misfire,
Whats next? What am I missing? I'm at a point where a stick of C4 would be the best way to go. I have read probably every thread ever created on this issue and done and checked everything recommended with no luck. Now I'm turning to you good people for advice and ideas.
Thanks
