98 Expy missfire??update

Reply Subscribe

Thread Tools

Search this Thread

Nov 23, 2009 | 07:19 AM

spotman

Thread Starter

Freshman User

Joined: Oct 2009

Posts: 31

Likes: 0

98 Expy missfire??*update*

Got a miss in my 98 expy 5.4. Will the computer store a code without setting off the CEL? Just started this weekend found one of the cops bolts loose. 2nd one from back on driverside. Any ideas on how to get a socket on that bolt? something on the fuel rail is in the way.
Thanks for any info!

Nov 23, 2009 | 09:42 AM

alloro

Fleet Owner

Joined: Apr 2008

Posts: 24,323

Likes: 5,133

From: 0,0,1

No it will not store a code without turning on the CEL. Loosen the mounting bolts for the fuel rail and you'll be able to move it around enough to get to the bolt.

Dec 4, 2009 | 08:05 PM

spotman

Thread Starter

Freshman User

Joined: Oct 2009

Posts: 31

Likes: 0

My Expy developed a miss around 1500 rpm while in overdrive. I could not get it to turn on the CEL. I was in autozone today and talked the guy into scanning it even though there was no CEL and he gt a #3 missfire code. I changed the cop and wow what an improvement. More power and smoother running all around. I guess it had been going for awhile. I'm now going to order new cops and plugs and change them all. However I did notice the elbows on the pvc valve hoses are looking rotted so I'm adding them to the list. Thanks for all the info on the forum keep it coming.

Dec 5, 2009 | 12:02 AM

alloro

Fleet Owner

Joined: Apr 2008

Posts: 24,323

Likes: 5,133

From: 0,0,1

Are you sure your CEL works? Does it light up when you first turn the key on?

Dec 5, 2009 | 11:24 AM

robc2064

Freshman User

Joined: Oct 2009

Posts: 28

Likes: 0

From: Deep South

I'm having the same problem with a misfire on #2 cylinder. Push it a few more days & it will get bad enough to turn on the CEL. Mine came on last night and the misfire has been there almost a week, but barely noticable until yesterday.

Dec 5, 2009 | 11:59 AM

pdqford

Logistics Pro

Joined: Jan 2001

Posts: 3,740

Likes: 37

From: Central NYS

Quote:

Originally Posted by alloro

No it will not store a code without turning on the CEL.

Some codes are referred to as "two trip codes" A "two trip code" will get stored in the 'pending file' the first time the PCM detects the condiction. If that code comes up in the next trip, it will then turn on the CEL. If it doesn't appear in the next trip, the PCM will clear the code from the 'pending' file. (I don't know if Autozone's scan tool can read 'pending' codes.)

Quote:

Originally Posted by robc2064

Push it a few more days & it will get bad enough to turn on the CEL.

If the CEL begins to flash on and off, better get it looked at quick, as it indicates that enough raw fuel is getting dumped into the cat to de$troy it.

Dec 5, 2009 | 04:42 PM

spotman

Thread Starter

Freshman User

Joined: Oct 2009

Posts: 31

Likes: 0

Yeah the CEL will come on when the ignition is first turned on.Don't no what scanner they used.I didn't look at the code but it just said #3 missfire detected on the scanner.