Hesitation after start...

[wilkin250r]

I have the oddest problem. Whenever I start my 93 Explorer in the morning, it always starts right up. It will run for about 1 min, and then the "check engine" light will flash several times. Immediatly following that, the engine will hesitate, almost die. After that, everything is fine and normal.

The simple fix is to just let the car warm up before driving it, but it gets rather annoying when I am in a hurry. Especially since the hesitation can often occur when I want to pull out into traffic.

Has anyone else experienced a problem like this? I tried disconnecting the battery to force the computer to reset itself, but it didn't fix the problem.

 

[metalhed]

Sounds like a dirty IAC valve.

Run a search on IAC, I know there's a thread that was posted pretty recently with pictures on how to clean it.

Goodluck.

 

[wilkin250r]

Forgive my ignorance. What is the IAC valve? I'm sure I can find it and clean it, but what IS it?

 

[Maniak]

Here's a pic to help find it..

IAC is Idle Air controller. Basically it lets in air around the throttle plate to give you "no-touch" starting to to adjust the idle when cold. It also increases the rpms when the a/c turns on. If the IAC isn't working normally the truck won't run after it is first started until it warms up. It can also make it hard to start without holding the throttle open a little (thats what it is supposed to do, by letting some air around the throttle plate).

~Mark

 

[wilkin250r]

Wow, thanks. Since my problems are associated with cold idle, it sounds like the IAC is the most likely culprit.

 

[Billy177]

sounds like a fuel system prolblem when was the last time the fuel filter was changed

 

[wilkin250r]

Originally posted by Billy177
sounds like a fuel system prolblem when was the last time the fuel filter was changed

I will be the first to admit, I'm not an expert, but I don't see how this can be a fuel problem. It only hesitates for a brief second, and then runs fine. I would figure the problem is computer-related. Some glitch as the computer chip runs though its boot-up when you start the car...

 

[Billy177]

it sounds as if there are air bubbles in the fuel line making it run lean for a few seconds causing the hesatation

 

[MattPersman]

you would have to have a huge leak to have air bubbles in your line all the time and you would know it cause fuel would be all over where ever it was leaking, they leave immediately as soon as you start the vehicle if you have opened it for service cause EFI under high pressure

that was a problem with carburator fuel systems but not the case with EFI

others are correct if your TPS voltage is too low can cause, defective IAC can cause this

 

[metalhed]

I was in a hurry during my first post, so I neglected to mention that this exact problem happened to me.

I usually had to wait for the thermostat to start rising before I could drive without it hesitating.. Tried cleaning the IAC, but it was completely saturated with grime, so I just replaced it.

That fixed my problem.. So it should work for yours too.

Let me know.