I have some troubleshooting problems on rough idle engine. Car will shake on open road when reaches a appro RPM of 2300. As soon as accelerator is released and re-engaged, it goes away. The check engine light is not on so I assume there is not fault engine code being stored/displayed. The fuel filter and spark plugs has been replaced recently, the alternator has a good output of 13.6v, battery load tested good and shows 750 CCA at 12.6v, the air filter has been cleaned and inspected. The oil is newly changed and has never shown any coolant in the oil. I used a lazer and checked several times that # 4 and #6 exhaust manifold are 300 degrees F hotter(580 degrees actual) than the other 4 cylinders-running at an average of 285 degrees. I switched the fuel injectors from the cooler, average cylinders to the hot cylinders to varify I didn't have 2 faulty injectors that were running lean. This did not make a difference in cylinder temp or rough idle. Is this normal for the #4 and #6 cylinders to run this hot? The only thing that I know what else to check is the fuel pressure on the fuel rail. Any suggestions I would appreciate
Sep 13, 2009 at 7:43 PM