Happy New Year FTE's!

I have 99' f-250 SD 5.4 automatic 4WD.

Out of the blue last week I started having starting problems.
Usually I just turn the key and it fires right up. Now I have to hold the gas pedal down half way to get it to go. If I miss the start the first time, I have to wait a few minutes to get it to start. Otherwise it'll just crank and crank. It doesn't matter if the engine is warm or cold.
Once it starts, it idle's and runs perfectly.

I did some searching and sounds like the IAC valve could be bad? Sounded like most people with IAC problems had idle problems as well.

Thoughts? Any other possiblity's?

 

make sure the easy stuff is good, (Batt, Batt cables, and such) and if you checked it post that with your question, Because those of us who have diagnosed this fault for years; this is the first things we check, and you would be surprised how many times something simple is the case.

 

I would start with checking your IAC.

 

PA -, New battery & cables spring of 2011. She cranks like new.
She just won't fire without some additional fuel. Or if it does start, (without the additional fuel) it's just for a second or two then stalls out...... Then I have to wait a few minutes to get her to go again.

My truck is a weekend driver. I do have an ever increasing hole in the muffler (that will be replaced soon). Could lack of back pressure be a cause?? Just Curious.....

Is there a way to check the IAC valve? Or just replace it and hope....?

Thanks for your help!! It's always appreciated!!

 

You dont have to proove it to me... I was just giving you some good life advise...

No the muffler would not make the truck act like this. It can be anyone of a hundred things. I would just keep bumping this message from time to time untill someone that has had your problem can answer.

I would never advocate throwing parts at a problem...

 

Emission System - Idle Air Control Motor Testing & Replacing - 1 of 2 - YouTube

give this a look-see

 

SteveO,
My 99 F250 V10 is doing the same thing. Usually tries to start and then quits. Cranks over well, but does not start. If I cycle the key a few times it will start (sometimes), but lately it has gotten worse and takes several key cycles. Seems to work okay when warmer weather, but it's getting colder here in the northeast. Keep looking as I will. If you find the cause please share with me and I'll do the same.

 

Sounds like exactly what my truck was doing right before the fuel pump went Tango Uniform.

Check your fuel pressure.

 

The thing about cycling the key; that rings a bell for me is... it primes the fuel system as if you just changed the fuel filter... Not saying that you did, but follow along with me for a min... its getting cold... in the maintenance field, which im in, we deal with all kinds of leaks due to constriction. Just the other day we had a truck loose its fuel prime because it had a leak small enough to let air into the system, but not fuel out. This may be both of your problems... its worth looking into
Hope this helps

 

first check the fuel pressure, then clean your IAC most of the time its the IAC is dirty. BUT sometimes cleaning the IAC doesnt fix the problem, ask me how i know. A new IAC solved my starting problem