River_Rat_459
05-10-2011, 16:40
I'm having a hell of a time figuring this one out. Has anyone had something similar happen with their car?
I have a 2000 Ford Taurus with the following:
24V V-6 DOHC, 3.0 L Duratec engine
134,000+ miles
Pretty well kept up on maintenance
Though the body is a little worse for wear, the engine and chassis are in good shape. I just put in a new set of spark plugs about 8,000 miles ago, so I think that can be ruled out. At any rate, here's the issue...
When the car has been sitting for a long enough for the engine to cool down completely (i.e. over three or four hours), it runs very badly the next time it is started. It misfires, knocks, stumbles, dies, etc. I can usually drive about three or more miles, and then it goes away until after the engine has cooled down. At that point, it starts up again.
I cannot find any vacuum leaks, and even if I did I believe the problem would be more consistent as a result. I ran an OBD II scan and get P0174 and P0171 routinely, which means that the fuel system is too lean. There are a few common problems listed at this site (http://repairpal.com/OBD-II-Code-P0171-and-P0174). Some forums have also listed possible problems such as EGR valves and oxygen sensors. I had the fuel injectors professionally cleaned out a couple of years ago.
I also ruled out water in the tank, as I ran the tank to nearly empty then used a couple of bottles of water removal (HEET), then filled the tank with fresh, higher octane gasoline.
As I mentioned, the problem is not consistent. It only seems to happen after the engine has fully cooled. If the morning is cooler (i.e. below 50 degrees Fahrenheit), it takes longer for the engine to settle down. The last few mornings, when the temperature was up over 60 degrees, the problem was still there, but didn't take as long to overcome...I only had to drive about two miles before it fixed itself.
I'm thinking of putting the focus on towards the mass airflow sensor first, since it seems to be the easiest thing to replace at the moment. I'm not sure beyond that, since there seems to be so many different things that can be wrong.
Has anyone else had anything similar happen with their car? Any advice (aside from the obvious "buy a new car":mad:) would be appreciated. Thanks!
I have a 2000 Ford Taurus with the following:
24V V-6 DOHC, 3.0 L Duratec engine
134,000+ miles
Pretty well kept up on maintenance
Though the body is a little worse for wear, the engine and chassis are in good shape. I just put in a new set of spark plugs about 8,000 miles ago, so I think that can be ruled out. At any rate, here's the issue...
When the car has been sitting for a long enough for the engine to cool down completely (i.e. over three or four hours), it runs very badly the next time it is started. It misfires, knocks, stumbles, dies, etc. I can usually drive about three or more miles, and then it goes away until after the engine has cooled down. At that point, it starts up again.
I cannot find any vacuum leaks, and even if I did I believe the problem would be more consistent as a result. I ran an OBD II scan and get P0174 and P0171 routinely, which means that the fuel system is too lean. There are a few common problems listed at this site (http://repairpal.com/OBD-II-Code-P0171-and-P0174). Some forums have also listed possible problems such as EGR valves and oxygen sensors. I had the fuel injectors professionally cleaned out a couple of years ago.
I also ruled out water in the tank, as I ran the tank to nearly empty then used a couple of bottles of water removal (HEET), then filled the tank with fresh, higher octane gasoline.
As I mentioned, the problem is not consistent. It only seems to happen after the engine has fully cooled. If the morning is cooler (i.e. below 50 degrees Fahrenheit), it takes longer for the engine to settle down. The last few mornings, when the temperature was up over 60 degrees, the problem was still there, but didn't take as long to overcome...I only had to drive about two miles before it fixed itself.
I'm thinking of putting the focus on towards the mass airflow sensor first, since it seems to be the easiest thing to replace at the moment. I'm not sure beyond that, since there seems to be so many different things that can be wrong.
Has anyone else had anything similar happen with their car? Any advice (aside from the obvious "buy a new car":mad:) would be appreciated. Thanks!