I have a 2001 Lincoln Ls V8 that keeps misfiring!
I have changed all 8 coil packs and 16 Plugs within 3 months. What else is there to do? At first I got the code and it was the 8th cylinder misfire, now its the 4th. I'm at my wits end with this thing. It is eating up my gas mileage and killing my power. If anybody has any suggestions please let me know. Thanks
There are a few things to do to when trying to diagnose a misfire. All vehicles are different, but here are a few places to start... 1)As you already know, using an OBDll scanner can diagnose which cylinder(s) is misfiring so that is ruled out...Even without engine scanners you can identify which cylinder is causing a dead misfire. Carefully disconnect one spark plug at a time. If the cylinder you are disconnecting is operating properly you will hear a change in RPM. If the cylinder you disabled is the bad cylinder you will see no change in engine behavior. 2)Check your ignition system. There are several steps to this. A)Which it sounds like you have done....Remove spark plugs and check to see if the electrodes look worn down or contaminated. Check your spark plug gap with a plug gapper to see if the electrode has worn down. B)I recommend for you to use a multimeter to check your spark plug wire resistance. They should read roughly between 2,000 - 12,000 Ohms. What you are really looking for is an open circuit in one of the wires. Bend the wires around and see if you lose continuity. C)Check cap and Rotor. Look for carbon tracking or extremely worn down rotor. 3)If you know your ignition system is operating properly you may want to check compression. You may already have the spark plugs out from your ignition check so it only takes a minute to check engine compression. 4)Fuel injection Service - The motorvac service works miracles. It is available at most repair facillities. Adding a can of fuel injector cleaner to your fuel tank is not ecnough to clean out a severely plugged injector. The motorvac solvent is much more potent and should only be used with a fuel injection cleaning machine. It is a good place to check with a hard to find misfire. 5)Vacuum leaks - A vacuum leak will cause a misfire. If the leak is near a certain cylinder that cylinder will misfire. You can try to find a leak by spraying down the engine carefully with carb cleaner. If you spray the location of the leak the RPMs will rise. You can also inject the intake manifold with smoke from a smoke machine and look to see if it leaks out anywhere it is not supposed to.
Thanks I will deff look into all of this. I am just wondering why when the car gets warm it stops running rough?
There should be two fans in your car. Only one of the fans is actually a cooling fan. That would be the one on the driver's side. The other one is a condenser fan for the A/C. Assuming the fan is coming on when it should, the rest of the circuit is fine. The problem just appears to be that the fan doesn't have the capacity to cool the engine down and simply driving does so that would be an indication that the fan motor is likely shot and just not spinning fast enough to move sufficient air for cooling. Aside from the fan, have you changed or checked the thermostat? aircondition compressor? Is there a sensor switch that controls the fans when the car is hot? And where is it located? Several simple questions, just run through the checklist and let me know if anything works and what doesn't. I'd like to help you figure this out.
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