Rough idle when cold.

[djk4013]

I have a 2004 Ford Explorer. About a week ago, my CHECK ENGINE SOON light came on. I took it to local Auto zone to have the code read. They said it was a mis-fire on #5 cylinder, we then replaced the plugs, plug wires and coil. The Check Engine soon light is not on now but, when I first start - cold, it idle's rough, after it runs for a few minutes it runs fine again.....any suggestions??

 

[BrooklynBay]

Welcome to this forum! What code number did you get? It might be a good idea to either scan it again or erase the memory, and have it learn a new pattern.

 

[djk4013]

I cannot remember what the code was at the time. The folks at Auto Zone said it was a misfire on #5 so, I replaced both the plugs and plug wires and then the coil pack. After that, the Check Engine Soon light went out, once the computer was reset at 55 mph and has not come back on since I replaced but, the car is still idiling rough at a cold start. Once it runs for a few miles or so, it seems to get better.

Do you think it could be a fuel filter, I haven't replaced it yet?

Thanks for the welcome....

 

[djk4013]

Also, forgot to ask. Can the error codes still be read if the CES light isn't on?

 

[BrooklynBay]

It's possible that the code might still be in there.

 

[sethmorgan]

but, the car is still idiling rough at a cold start. Once it runs for a few miles or so, it seems to get better.

Do you think it could be a fuel filter, I haven't replaced it yet?

Thanks for the welcome....

Sounds like it might be a gasket leaking creating a vacuum leak. Intake manifold maybe? As the truck warms, everything expands, sealing back up.

 

[rich250]

could be the IAC ,you could try pulling it out and cleaning with eletrical cleaner.

 

[djk4013]

Where is the IAC?

Could the problem possibly be an EGR valve or a DPFE sensor? And, if so where are these located?

Thank you all for your help with this, it's driving me nuts!

 

[rich250]

which engine do you have

 

[djk4013]

It's a 4.0 liter engine.

 

[djk4013]

Code P305

The CEL light came on today I took it to Auto Zone to read the code, it's a P305. Also said the 5th cyclinder isn't getting a spark. I've already replaced the spark plugs, spark plug wires and coil pack. What do I do now?

 

[kenlewis11]

1997 Explorer 4.0 SOHC

I am having trouble with my Explorer idling rough on semi-cold start up. A dead cold start up in the morning is fine, but at lunch or other times during the day, it will idle very rough for 15 seconds or maybe 30 on startup. Then something clicks and it smoothes right out. Once it clicks it revs up to a cold start up rpm then calms down to normal idle. Its almost like normal startup mode is delayed until it gathers its brains.

Its seems to be irrespective of outdoor temperature or humidity. Changed the IAC valve, didn't work.

My mechanic is baffled. Ford dealer wants a piece of it....along with a piece of my wallet.