Ford Focus hard start and stumbling

[LatLong]

I have a 2005 Ford Focus Wagon. 2.0 4 cyl. with a 5 spd. 118k miles. The car starts fine cold but when it is warmed up and sits for a short while(up to a couple hours depending on outside temp) when I go to start it it starts hard. It will crank, I let up on the key and try again. Sometimes this takes 3 or 4 tries before the car will start. When it does it will stumble and barely idle. If I tap the gas it smooths out and idles fine. The car has had plugs and a fuel filter at about 80k. Thanks for any help.

[fishing tech]

Fuel filter should be done every 15k miles. Especailly on a focus.

Sounds like a fuel problem. The pump may be going out. I would try a new fuel filter first.

[LatLong]

Just out of curiosity..why would the fact that it is a Focus have a bearing on the fuel filter interval? Are they especially finicky about fuel pressure?

[fishing tech]

Kind of known for fuel pumps going out. The ones that I run into the filters were plugged on 75% of them. I have an 01 and the filter has been changed every 15k. Original pump at 160k miles.

[LatLong]

Well...looks like a fuel filter is next on the list. I'll post again if the problem persists. Thanks.

[LatLong]

Changed the fuel filter last weekend and figured I'd give it some time to see if the issue was fixed. A couple times I've had to crank it over a little longer than usual but it started and ran without the stumbling.

[fishing tech]

You will have a longer vrank with the cold weather. Sounds like it is running better though.

[LatLong]

The longer cranks are always when the car is warm. When it's cold, like in the morning after sitting all night it fires right up. But yes it seems to be running better. Thanks for the advice on the fuel filter.

[LatLong]

Well , my problem still exists. The last couple nights I've plugged the car in and i get the hard start in the morning. If I let the car sit without the block heater plugged in it starts fine. Could this be the cylinder head temp sensor? No CEL yet. Is there a way to test the sensor?

[JOHNBIGDOG]

Just for giggles try disconnecting the Mass air flow sensor warm and report the results...

I would agree that a sensor is biased...

this will set a code if done twice btw..

[LatLong]

sorry it took so long to get back...had a frozen water line at home to deal with. i unplugged the MAF sensor with the car good and warmed up(car running). the only thing that happened was the engine changed pitch for a second and then ran just like it should. it might have idled just a tad lower.

[JOHNBIGDOG]

did you shut it off and try restarting it without the MAF disconnected?(should have been more specific.)

[LatLong]

No, I just disconnected it and nothing changed so I hooked it back up with it still running. So I should unhook the MAF with the car warm and running...then turn it off and try restart with the MAF disconnected?

[JOHNBIGDOG]

try it and see what happens, if it starts the same its prob. not the cause, (When the concern is present)try pressing the accelerator just a little, then start. Idle Air Control may be sticking.

[JOHNBIGDOG]

Also if you could get a hold of a fuel pressure gauge and see if there is sufficient fuel pressure when the concern is happening....

[LatLong]

I tried the procedure you suggested and it started right up. tripped the CEL so i'll have to clear the code but that's no big deal. what would you suggest for a fuel pressure gauge? might as well have one of those too! can't have too many tools. i'll give the accelerator thing a try next time it gives me trouble.

[JOHNBIGDOG]

Well its a possibilitiy that the MAF is biased(doesnt work correctly) But befor I replace and expensive part I would look @ the fuel pressure. Any god parts store should have a decent gauge, I am biased twords NAPA, or Carquest. Fuel pressure for that vehicle should be 49psi Key On Engine Off, 39psi Key On Engine Running hard acceleration.

On a second note there is a TSB number 05-9-16:

ISSUE:

Some 2005 Focus vehicles equipped with MTX-75 manual transaxles, may exhibit a long crank or hard start condition with no malfunction indicator lamp (MIL) and no diagnostic trouble codes (DTCs) present.

ACTION:

Reprogram the powertrain control module (PCM) to the latest level using WDS (edited)

The PCM reprogram May or May NOT help, just something I found...