Check Engine problems....98 Expedition 5.4L
Tuned
Joined: Sep 2003
Posts: 296
Likes: 0
From: north carolina
Be sure that you inspect the boot between the COP and the plug for cracks. I have actually gotten misfire codes resulting from deterioration of the rubber and cracks allowing the secondary to ground. These boots are $3-4 at the parts store----a lot cheaper than replacing the COP.
New User
Joined: Jun 2010
Posts: 5
Likes: 0
My engine check light blinks 54 times while driving down the highway, twice today. It's been intermittently running poorly , I.E. rough idle, shakes in drive and terrible mileage. I reset the engine light by disconnecting the battery and it ran great again for a day, but now uugh! I see all your post and find them very informative, what should I check for? 1998 f150 4x4 5.4L
Hotshot
Joined: Jan 2004
Posts: 19,762
Likes: 1,079
From: St Louis
My engine check light blinks 54 times while driving down the highway, twice today. It's been intermittently running poorly , I.E. rough idle, shakes in drive and terrible mileage. I reset the engine light by disconnecting the battery and it ran great again for a day, but now uugh! I see all your post and find them very informative, what should I check for? 1998 f150 4x4 5.4L
Probably a misfire, but the fault codes will point you in the right direction.
Fleet Owner
Joined: Apr 2008
Posts: 24,318
Likes: 5,128
From: 0,0,1
Stop driving it or figure on replacing your catalytic converters. A blinking CEL means there is enough raw fuel being dumped into the exhaust to damage the cats.
New User
Joined: Dec 2010
Posts: 2
Likes: 0
Can anyone help? I have a 99 expedition 5.4L V8 the Truck is nice had engine problems last year while working on the truck a friend dropped a bolt down one of the spark plug holes. screwed the engine. This year I replaced the engine, Now the same driveability problems are back. 1. excessive engine vibration. Was told to do a power balance test, But the pcm corrects the problem before RPM DROP. 2. No misfire codes. Codes are for cat below thershold bank 2. And p1000 system readiness ont complete.
Studing to become a tech, Instructor not a lot of help with outside projects.
Studing to become a tech, Instructor not a lot of help with outside projects.
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Logistics Pro
Joined: Jan 2001
Posts: 3,740
Likes: 37
From: Central NYS
Cat below threshold could be separate issue, or it might be a by product of the vacuum/exhaust leak.
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