[witmerrace]

The car is a 2006 Si, V-6 5 speed manual. Great car, I have had no trouble since buying new. I do all maintenance. Car has 115k miles. Changed to new platinum plugs at 88k miles.

I got a 'evap systm leak' code last week, checked gas gap -- was OK. Car had an almost cut out miss (engine wants to quit) between 2k & 3.5k rpms. Kick the clutch in so no load on engine & rev past miss to get power back. Get past that band, car runs OK. OR, & this is odd, if I fill gas tank completely car runs great. This missfire starts when gas level is below 1/4?

I changed out the air filter last week (to a K&N) but don't see how that could be related.

I'm guessing something in evap system, but what? Any other ideas? I'd appreciate any help.

 

[BigAlDJ]

Try purge solenoid valve.
Click on this

 

[flipper66]

Sounds like you have a dying fuel pump. the pump is intank so that the fuel will cool the fuel pump. Running the car down to E is rough on the pump as it heats up.......

Just a guess

Purge valve should have no bearings on the car bucking.

 

[flipper66]

btw, what brand and style platinum plugs did you put in.

Platinum plugs are the most common plugs to have pre-ignition issues with so you may consider dumping those things.

 

[BigAlDJ]

Sounds like you have a dying fuel pump. the pump is intank so that the fuel will cool the fuel pump. Running the car down to E is rough on the pump as it heats up.......

I thought briefly about this but I hope it isn't---$$$$$$$$$$$
Personally I don't let my fuel go below 1/4, 1/3 to 1/2 in winter.

 

[flipper66]

no garrentee, he would need to use a fuel pressure checker to verify.

 

[witmerrace]

The car is a 2006 Si, V-6 5 speed manual. Great car, I have had no trouble since buying new. I do all maintenance. Car has 115k miles. Changed to new platinum plugs at 88k miles.

I got a 'evap systm leak' code last week, checked gas gap -- was OK. Car had an almost cut out miss (engine wants to quit) between 2k & 3.5k rpms. Kick the clutch in so no load on engine & rev past miss to get power back. Get past that band, car runs OK. OR, & this is odd, if I fill gas tank completely car runs great. This missfire starts when gas level is below 1/4?

I changed out the air filter last week (to a K&N) but don't see how that could be related.

I'm guessing something in evap system, but what? Any other ideas? I'd appreciate any help.

The problem was a FAILING FUEL PUMP. Now fixed @ $790.00. Was able to have the problem (miss when tank below 1/4 tank fuel, fill tank & problem disappeared until almost empty) repeat itself 3 times. Fuel pressure was right at the computer shut off value, so low fuel dropped fuel pressure below (temporarily) computer required fuel pressure. So breasty66 was right, THANKS to all who posted a possible problem/solution. ,,,,,,,,,,, REW

 

[Used03M6s]

The problem was a FAILING FUEL PUMP. Now fixed @ $790.00. Was able to have the problem (miss when tank below 1/4 tank fuel, fill tank & problem disappeared until almost empty) repeat itself 3 times. Fuel pressure was right at the computer shut off value, so low fuel dropped fuel pressure below (temporarily) computer required fuel pressure. So breasty66 was right, THANKS to all who posted a possible problem/solution. ,,,,,,,,,,, REW

HAHA i like!

 

[flipper66]

lol

glad you got it all straightened out. no way in hell I would pay someone 800 bucks to replace the fuel pump, but glad you got it figured out.

 

[thanh]

Shiet. 800 bucks...That's god damn expensive. I wonder if there's a ford alternative replacement?

 

[oregonducks]

damn i thought those things were like 450$

 

[flipper66]

They are ~450 bucks+ labor to install would be my guess.

@than, I believe the story goes it is a ford designed fuel pump. the Pump is encased on a solid plastic unit as well as the fuel filter. thats why if you have a bad filter or bad pump..... the solution to either is the same thing.

It is an in tank unit and most shops will tell you that you have to drop the tank to remove. this is a fallacy and I have replaced a 1/2 douzen "in tank" units by simply removing the pump and wiping off the few drips of fuel that come with it.

either process will result in a few drops of fuel excaping...... 1 will be on the floor, 1 will be a few drops on a near by rag if done properly.

beyond that it should be a 3-5 min swap beyond that.