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I work at a shop where we have a 2003 Ford Ranger 2wd Auto flex fuel that seems to have a fueling issue at engine speeds above 3,000 rpm what I’ve done is fix vacuum leaks checked the fuel injectors replaced fuel filter spark plugs and camshaft synchronizer. It idles okay but above 3,000 rpm driving it has no power and is bogging sounds to be pinging or spark knocking and throwing dtc codes p0175 and p0171 I’ve tried different coil pack both upstream oxygen sensors checked for clogged cats cleaned the maf sensor and everything seems to be within spec I have not done a compression test yet planned on that tomorrow just trying to get ideas on what could be the issue I don’t believe it’s the rev limiter gifting due to the data pid showing it being in drive when I have it in drive and park or neutral when it’s in park or neutral any help would greatly be appreciated since this thing has been whooping my butt all week.
Maybe check misfires on Mode 6 on scantool. Also check your fuel. Just disconnect hose at rail and cycle key to get a sample in a glass jar.
Check fuel pressure while driving
It doesn’t show any misfires on any cylinder even on the cylinder power balance test everything looks normal but you can notice a misfire more at higher rpm’s it’s hard to really check fuel pressure while driving because basically the condition it’s running makes it practically undriveable. Tomorrow I’m gonna recheck the maf sensor and the fuel pressure to be sure I do know that last I checked it was 55 psi KOEO and 60 psi KOER at idle and higher rpm’s I did notice that both banks go lean on the upstream o2 sensors at WOT so that leads me to believe a fuel delivery issue I’ll get a fuel sample tomorrow also.
Rechecked fuel pressure this morning and it finally showed the fuel pump being weak as where before it would instantly shoot to 55 psi, this morning it only showed 10 psi fuel pressure so installing a new pump in the morning to verify that was the issue and will post my results after
Just to do an update on the issue with this truck it was a clogged bank 2 catalytic converter which I’m gonna say was caused by the poor fuel delivery I also replaced the plug wires because a couple of them were broken down and causing weak spark on a couple of cylinders.
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