sonyman Posted May 10, 2007 Share Posted May 10, 2007 For a few months now, my LS400 has had a misfire between 45-60 MPH. Applying throttle pressure only makes it worse. It makes its presence known as subtle vibration. I changed the spark plugs, wires, caps and rotors and gained some power, but it didn't fix the problem. The last time I took my car in to the shop my mechanic told me it was a misfire, but he doesn't recall making this diagnosis and now doesn't seem to know the cause of the problem. Another reason why he thought it was a misfire is because one time I started the car and the engine was violently shaking for 20-30 seconds before it smoothed out. If it's not a misfire, then what is it, and what can I do to fix it? Quote Link to comment Share on other sites More sharing options...
sonyman Posted May 10, 2007 Author Share Posted May 10, 2007 After driving the car some today, I have found that the mis is actually still present at higher speeds, but barely detectable. For all I know, it's the same way at lower speeds but too suttle to notice. Quote Link to comment Share on other sites More sharing options...
etex Posted May 10, 2007 Share Posted May 10, 2007 Try a search on "ignition coils" and see if you find some similarities. Quote Link to comment Share on other sites More sharing options...
sonyman Posted May 10, 2007 Author Share Posted May 10, 2007 Try a search on "ignition coils" and see if you find some similarities. I thought it might be a coil, but my mechanic says that typically, if a coil goes bad, it doesn't work. Period. Meaning, I'd be running on 4 cylinders. What's your take? Quote Link to comment Share on other sites More sharing options...
dcfish Posted May 10, 2007 Share Posted May 10, 2007 Try a search on "ignition coils" and see if you find some similarities. I thought it might be a coil, but my mechanic says that typically, if a coil goes bad, it doesn't work. Period. Meaning, I'd be running on 4 cylinders. What's your take? Intermittent fuel injector ? Have them tested. Quote Link to comment Share on other sites More sharing options...
LScott400 Posted May 10, 2007 Share Posted May 10, 2007 I thought it might be a coil, but my mechanic says that typically, if a coil goes bad, it doesn't work. Period. Meaning, I'd be running on 4 cylinders. What's your take? Here is a Link that explains coils and makes the point that a basic resistance test may test good while the coil may start to fail under load. Quote Link to comment Share on other sites More sharing options...
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