98 Expy Rough Idle

Reply Subscribe

Thread Tools

Search this Thread

Jan 2, 2006 | 03:24 PM

marinazaz

Thread Starter

Freshman User

Joined: Dec 2005

Posts: 29

Likes: 0

98 Expy Rough Idle

Ive had my Expy for a year. It has about 98K miles now and had a noticably rough idle. I am going to start by changing the plugs, any suggestions.
I idles rough moslty when it is completely warmed up to normal temp

Last edited by marinazaz; Jan 2, 2006 at 03:25 PM. Reason: type

Jan 12, 2006 | 12:11 PM

99ExpeditionXLT

Junior User

Joined: Jul 2004

Posts: 59

Likes: 0

You may want to check a for a cracked hose in the rear engine compartment, next to the firewall. I believe it is in the piping for the EGR system. The hose is normally molded into a 90 degree bend. It tends to crack and allow unregulated air into the intake. This additional air upsets the air to fuel ratio, mostly at idle. It makes your engine run rough.

Jan 12, 2006 | 10:05 PM

marinazaz

Thread Starter

Freshman User

Joined: Dec 2005

Posts: 29

Likes: 0

Thanks XLT, Ill look for that too.

I changed plugs and checked coils
Enging runs like new now, what a difference new plugs make at 90K+miles.

Jan 13, 2006 | 01:10 AM

chrisc65

New User

Joined: Jan 2006

Posts: 1

Likes: 0

That is good news. Same situation here.

I have heard that it is a pain to change out the plugs. A local place by me said they would do it but they would also need to replace the coils.

4hour job at least + parts = $800.

How much time/ $ did it take you? I assume you didn't change out the coils?

Last edited by IB Tim; Jan 13, 2006 at 06:12 AM.

Jan 13, 2006 | 06:12 AM

IB Tim

FTE Leadership Emeritus

Joined: Jan 2003

Posts: 161,999

Likes: 75

From: 3rd Rock

...Welcome to Ford Truck Enthusiasts!

We are happy you have chosen the best source for Fords!

Enjoy FTE....and
JOIN CLUB FTE -SUPPORT THE FORUMS!
…..See you on the boards.

Jan 14, 2006 | 12:16 AM

marinazaz

Thread Starter

Freshman User

Joined: Dec 2005

Posts: 29

Likes: 0

Quote:

Originally Posted by chrisc65

I paid 5.00 each plug at the dealer although I think Autozone had the same plugs for 2 dollars. They are the double platinum according to the guy at Ford. As for the coils, I did not replace one. Two checked out bad according to the specs. The bad ones read around 12K on the secondary, they should read 6K. One I also broke the spring inside the boot while pulling it out. I was short on cash so I put everything back together including the broken spring and all is well so far. I plan on getting the coil boot for around 5 bucks at autozone. I also found some coils on Ebay from 25.00 to 50.00 each. New, they are 50.00 at Autozone. I moved the bad coils to the front of the engine (#1 and #5) for easy access thinking I will replace them within the next month when I have some time. This forum had some pretty handy instructions on getting those plugs out. It took me around 5 hours, taking my time.

Note that Ford changed the part number on the plug from the originals. They have more thread also.

Apr 22, 2006 | 10:48 PM

Mountain Cat

Freshman User

Joined: Apr 2006

Posts: 37

Likes: 0

I agree with 99ExpeditionXLT. I also had this hose in the back of the engine with a crack in it on the corner. I replaced it and the engine ran smoother. It is easiest to reach from the passenger side and may take a little bit of contortion abilities with your arm.
-- Mountain Cat