i have a 97 xjr, and two days ago on the highway my cel came on, car started to misfire, i went to local place to scan the codes and heres what i got P0302 which is misfire on cyl 2, and p1313 which i believe is lean surge, i have a few ignition coils from my other jag that i owned a while back so i replaced the ignition coil on cyl2, it ran fine for about 30-40 min drive and then the symptoms came back again, same codes, i replaced the ignition coil on cyl 2 with another spare one, 20-30 min drive and car starts to miss fire, and same codes pop up, as of right now im completely clueless what to do next, if anyone can point me in the right direction, all the help will be appreciated, thnx in advance .
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Sounds as if something is stressing that one coil. I don't claim to know that much about what would cause something like that, maybe the wrong plugs, or a wide gap on plug number 2? what does everyone else think? Maybe those things wouldn't cause this problem.....
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sparkenzap
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Aug 22, 2023
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First, although it is perhaps counter-intuitive, a misfire can cause a lean code. The oxygen sensors are just that-oxygen sensors. So if a cylinder is not firing, then you will have the oxygen that was supposed to be used burning going into the exhaust.
But P-1313 is a serious misfire code according to JTIS, NOT lean surge. I would look at the compression in the offending cylinder, then get a scope on the coil. I suspect you are going to find low compression, but maybe you will be lucky and have either a bad primary circuit for the coil, or even a plugged fuel injector. If the car smells rich while this is going on, you can probably eliminate the injector.
The coil primary circuit is fired from the ecu, so there is no cheap parts exchange to find a bad primary circuit. I would certainly scope it before I assumed it was a bad ecu.-
But P-1313 is a serious misfire code according to JTIS, NOT lean surge. I would look at the compression in the offending cylinder, then get a scope on the coil. I suspect you are going to find low compression, but maybe you will be lucky and have either a bad primary circuit for the coil, or even a plugged fuel injector. If the car smells rich while this is going on, you can probably eliminate the injector.
The coil primary circuit is fired from the ecu, so there is no cheap parts exchange to find a bad primary circuit. I would certainly scope it before I assumed it was a bad ecu.-
fixed, got new set of plugs and new coil, ran a bottle of seafoam with 94 octane gas, works like a charm, my other question is where can i find a vacuum line that feeds into the intake manifold, but after the intercooler, i want to seafoam it, but the only one i found is the brakebooster, but it will run thrue the supercharger, and i dont know if it will damage it