My 2001 Taurus SEL (with Duratech DOHC engine) has recently had problems with intermittent engine misses. It usually happens when cold, but not always. It sometimes happens taking off from a light. I have also had it occur when accelerating to get on to the freeway. Sometimes the car runs fine for 20 minutes without any problem (it actually runs great). There is no check engine light whatsoever. I checked for codes and there are none.
The car was recently "smogged" and had very low emissions. I attribute this to the engine still having good compression and being a very good condition.
The plugs and wires were replaced at 100,000 with OEM Ford parts. I have since rechecked the plugs and they are burning very clean.
When the problem started, I replaced the inline fuel filter. I hooked up and inline fuel pressure tester and everything is within specs (57 lbs). With the pressure tester left in place while driving, the pressure actually goes up when the engine misses. My guess is that the regulator is working fine. I do not believe the fuel pump is the problem.
I have since taken apart the intake manifold and checked the fuel injectors (all about 13.5 ohms), tie-wrapped down the electical connectors to the injectors (the clips all broke off) and cleaned all of the emission and engine control parts (MAS etc) using proper parts cleaner prescribed. I checked all electrical connections (even cleaning them with contact cleaner) and everything looks good.
The O-2 sensors have never been replaced. Should I suspect them even though the car is not throwing codes? They have over 100K on them, so perhaps it would be worth replacing them for better fuel economy? I have noticed gas mileage decreasing with this problem, so perhaps this is my culprit? How about EGR components?
I'd guess that there is no definitive answer, but perhaps you can direct me how to proceed with troubleshooting this beast. I am starting to think I will figure this out when pigs fly.
Very Appreciated!
The car was recently "smogged" and had very low emissions. I attribute this to the engine still having good compression and being a very good condition.
The plugs and wires were replaced at 100,000 with OEM Ford parts. I have since rechecked the plugs and they are burning very clean.
When the problem started, I replaced the inline fuel filter. I hooked up and inline fuel pressure tester and everything is within specs (57 lbs). With the pressure tester left in place while driving, the pressure actually goes up when the engine misses. My guess is that the regulator is working fine. I do not believe the fuel pump is the problem.
I have since taken apart the intake manifold and checked the fuel injectors (all about 13.5 ohms), tie-wrapped down the electical connectors to the injectors (the clips all broke off) and cleaned all of the emission and engine control parts (MAS etc) using proper parts cleaner prescribed. I checked all electrical connections (even cleaning them with contact cleaner) and everything looks good.
The O-2 sensors have never been replaced. Should I suspect them even though the car is not throwing codes? They have over 100K on them, so perhaps it would be worth replacing them for better fuel economy? I have noticed gas mileage decreasing with this problem, so perhaps this is my culprit? How about EGR components?
I'd guess that there is no definitive answer, but perhaps you can direct me how to proceed with troubleshooting this beast. I am starting to think I will figure this out when pigs fly.
Very Appreciated!
Aug 6, 2009 at 11:58 PM