When I start my truck, first thing in the morning, and I wait... say... ten seconds before I drop it in gear and go; it'll hesitate coming off idle.

If I wait 30 seconds... it doesn't happen.

Is there some sensor, somewhere, that needs to warm up a bit before it starts informing the computer properly?

Is there anything I can do about it?

Not that I mind waiting 30 seconds before I go but... well, actually, I do mind... I would like to be able to start the thing in gear with my foot half way to the floor and tear the skins off it in the driveway.

 

I have the same issue with my 05 5.4.. I would be interested to know why as well..

Thanks

 

McCart...

No answers in here, eh?

Betcha if you asked whether you should black out your headlights or just go charcoal you'd get about 50 responses.


You being from Cali; I guess the problem isn't about "cold" starts (I thought maybe... 'cause our overnight temperatures, in the summer, are often in the 50's or even 40's).


I'm due for service in the next month or so, I'll ask the technician and post the anser in here (if he has one).

 

its normal for it to idle high right after starting. timing is retarded and RPM is increased to help warm up the engine and get into closed loop ASAP. its an emissions thing. Dont worry about it.

 

Just got back from my (hated) local ford service centre.

Oil change. Recal (vacuum brake booster line)

Kept it for an extra day to look into the hesitation thing. No clue.

 

Just a thought, when was the last time you changed the fuel filter?

 

Torque Converter in trans low on fluid?

 

I think... if it were a filter, or a tranny, or a vacuum hose, or a sensor... it would happen all the time, or every start, or whenever it was cold... but it doesn't. It happens every morning, only in the morning, only when I first start the thing.

I think it's software... (I used to test software for a living; this feels like software to me).

I think that somewhere in the pc is some piece of code that needs to read or recalibrate "sensor xyz" once per 24-hour period, and when it's reading sensor xyz, while the engine is in fast-idle and the throttle is in position "b"... the cpu has a momentary (say, four clock cycles) crap out.

That's what I think.

I'm going to get a data logger and see what's what.

 

Check your trans fluid before you start getting technical with data loggers and such.

 

The dealer should do a PCM reflash and then it should be ok.

 

Tranny fluid is good. Almost time for a flush and refil though...

 

^Yep. It's normal

 

Oh... high idle is normal... OK

and that explains why my engine hesitates, rather than reving smoothly in response to throtle input... ... ... how?

 

yes. high idle is normal on start up. it should take a second to drop down and stabalize, then you are good to go. at least thats how it is with every car i've had. most other peoples vehicles too. if its not normal, we all have issues.

30 seconds for it to work is NOT normal though. if it is after low temps over night it would be. the engine needs to warm up. thats why you have a high idle at start up.

 

I don't think he is complaining about the high idle. We have established that this is normal. What he wants to nail down is the *hesitation* issue.

With an electronic throttle, it almost has to be software. No IAC valve to gunk up. A PCM reflash may be the solution, discuss this with your dealer.