Rough Idle/Engine Stalling on 2006 Ford Taurus

I have an 06 Taurus with 80,000 miles with a rough idle and misfire. Car runs fine when driving. The bigger problem with this however is that randomly when I am at a stoplight or sitting in traffic, etc where I have to idle for very long the car will start missing really bad and doesn't hardly have the power to pull back out. (Like so bad you think the car is going to die right there) I have a 3 yr old so I am terrified it is going to get me stuck in traffic and get us rear-ended. Pull off the road, turn it off for 5-10 minutes and it's fine again. First time it did this the engine light came on & the code was for a fuel rail pressure sensor. Replaced this but it didn't fix the problem. Engine light came on again but code just says "random misfire". Since this problem has arose I have replaced the fuel rail pressure sensor, the coil, the idle air sensor, all spark plugs & wires and we have ran fuel injector cleaner thru the gas tank. I've had this to three different mechanics including the Ford dealership with no success. Any help is greatly appreciated. (Also, this may be totally unrelated but it seems to be worse the hotter the weather is)

by in Duff, TN on February 20, 2011
2 answers
ANSWER by , February 20, 2011
I suspect that your problem is more complicated,but since it's a simple,inexpensive prodedure that you didn't mention doing, I'd put in a new gas filter.
ANSWER by , February 20, 2011
As the temperature increases, fuel gets more volatile. It's true that there are multiple blends of fuel per year supplied to gas stations for us to fill our cars with. They are forumated for the climates you drive in. Cold weather fuel is different than hot weather fuel. If you have abnormally hot weather during a time when cold weather fuel is available, all kinds of driveability problems can happen...rough idle, stumbling, poor performance. Usually that doesn't set a code, though, so that's where my concern comes in. It seems that you've done everything reasonable to solve your issue. When the problem is occuring, I'd love to know what the fuel pump pressure actually is. I get the feeling it may be producing less volume and less pressure. Fuel pumps are very temperature sensative and can fail when warm too. You need to find a technician with patience and strong expertise to help you out first hand. Your problem can be solved with time invested and effort. And recreating the problem during testing is a must.