99 Expy Running Rough/Engine Light On
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Joined: Jul 2003
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99 Expy Running Rough/Engine Light On
Our '99 Expedition (84K miles, 5.4 Triton) is running rough, missing, etc. We've replaced the air & fuel filters, and one of the oxygen sensors. the engine warning light ("service soon") is on (and off, and on...). I'm not too mechanical, but can change (normal!) plugs. Where in the world ARE the plugs on this thing? What else should we check? we can't afford to take it to our local Ford dealer and have them charge us $52 just to hook it up to the computer & tell us it has a problem...! DUH! Any suggestions? Thanks!
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Joined: Aug 2002
Posts: 12,679
Likes: 15
From: BC, Canada
99 Expy Running Rough/Engine Light On
Hi mhardesty and welcome to FTE 
The best place to start would be to get your Expy scanned for trouble codes. That will hopefully tell you which cylinder is misfiring. Apparently Autozones will do that for free if you have one close by.
Chances are pretty good it needs new spark plugs unless they have been changed before. The most common one to misfire is #4....back one on the passenger's side. Quite often the heater hose clamp right above it is loose and it leaks coolant onto the coil and plug which kills it.
The spark plugs are between the valve covers and intake manifold. There are no plug wires. Each plug has it's own COP (Coil On Plug). You'll see them next to the fuel injectors. The COPs are about 1 1/2" across the top, round if looking straight down on them and have one 2 wire connector going to them.
In the 97+ F150 forum I've posted general instructions for replacing the plugs and others have added their own tips too.
The first time you do them it will take a while and you probably wont be too impressed but it's not really as bad as it first looks.
Just plan on spending a few hours under the hood.
The best place to start would be to get your Expy scanned for trouble codes. That will hopefully tell you which cylinder is misfiring. Apparently Autozones will do that for free if you have one close by.
Chances are pretty good it needs new spark plugs unless they have been changed before. The most common one to misfire is #4....back one on the passenger's side. Quite often the heater hose clamp right above it is loose and it leaks coolant onto the coil and plug which kills it.
The spark plugs are between the valve covers and intake manifold. There are no plug wires. Each plug has it's own COP (Coil On Plug). You'll see them next to the fuel injectors. The COPs are about 1 1/2" across the top, round if looking straight down on them and have one 2 wire connector going to them.
In the 97+ F150 forum I've posted general instructions for replacing the plugs and others have added their own tips too.
The first time you do them it will take a while and you probably wont be too impressed but it's not really as bad as it first looks.
Just plan on spending a few hours under the hood.
