What is going on?

[OXX1973]

I have a 1998 Ford Expedition XLT 4x4 with the 5.4. My CEL came on and when I checked it with my scanner it threw the Cylinder 4 misfire code. I replaced it this weekend and I am no longer getting a CEL nor is there a pending code showing. When the engine is cold and running, it drives smooth but after about 10 minutes of driving I start getting vibrations and what can only be described as misfires. I checked all my COPs by pulling the fuel injector harness to see if it would throw a CEL or if it would drop the rpms but no such luck. I am officially stuck and need help.

Thank you

 

[CaperCanadian]

I had the same thing on mine, I had a bad plug, would work fine cold, and start bucking when it warmed up. Pull the plugs and give them a check.

 

[docraymund]

Check the coolant temperature sensor. It is the primary sensor used during open loop conditions.

 

[OXX1973]

Check the coolant temperature sensor. It is the primary sensor used during open loop conditions.

Would this cause my expedition to act like it is misfiring?

 

[1955moose]

In your post you didn't say what you replaced? Was it the coil, wire, what? You stated the code went away, if you have a miss, the order of things, usually is to run diagnostic codes, which you did, run a fuel pressure test, to eliminate a weak fuel pump, clogged filter, or fuel pump wiring. I would change all 8 spark plugs with motor craft plugs, along with spark plug wires. Do you have the coil on plugs, or the early style coil/ wires? For what it's worth that's where I'd start. Working out of your home a full tune-up is where your probably heading. As tempting as it is, don't change coils, with the cheaper Asian ones available online. You can cause more problems. These vehicles tend to like oem Ford parts, keep us posted what fixes your hiccups.


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[OXX1973]

In your post you didn't say what you replaced? Was it the coil, wire, what? You stated the code went away, if you have a miss, the order of things, usually is to run diagnostic codes, which you did, run a fuel pressure test, to eliminate a weak fuel pump, clogged filter, or fuel pump wiring. I would change all 8 spark plugs with motor craft plugs, along with spark plug wires. Do you have the coil on plugs, or the early style coil/ wires? For what it's worth that's where I'd start. Working out of your home a full tune-up is where your probably heading. As tempting as it is, don't change coils, with the cheaper Asian ones available online. You can cause more problems. These vehicles tend to like oem Ford parts, keep us posted what fixes your hiccups.


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Sorry for not giving all the information. Yes I changed the Coil on Plug (COP) for the #4 cylinder. I had a tune up a couple of years ago that involved replacing all of my plugs with motorcraft plugs and the fuel filter. I thought they would change all of the COPs but they did not and the itemized receipt shows they did not charge for them so at least I did not get swindled. I have already replaced 3 COPs with motercraft COPs. I do not the ability to run a fuel pressure test but when I pulled the wire harness of the fuel injectors one by one, there was a noticeable drop in RPMs

 

[1955moose]

You can usually borrow a fuel pressure tester from the name brand auto parts stores, like auto zone and Oreillys. It's not a bad idea to purchase a mid priced one, under $100.00 just to have. Missing under load can be fuel or electrical related, is why you do diagnostic, so you don't look like curly from the three stooges, doing his spinning in a circle routine. Easiest way to tell electrical misfires vs fuel, is electrical makes a strong off/ on bucking, fuel make a softer sputtering, and bad coils/ boots act up real bad at highway speeds under constant throttle. If you have no particular cylinder codes, could be insufficient fuel. You might also want to use a noid light set on your injector harness,to be sure all 8 are getting power and ground. If everything electrical, fuel, compression checks out, you might consider injection clean out. Keep us posted on yours/ mechanics diagnosis.


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[OXX1973]

So my expedition finally through a pending code. P0303 (misfire in cylinder 3). I took off the COP and exchanged it for cylinder 2 and it still through p0303. I pulled the plug and it was pretty nasty like someone left paper on the spark plug well. I cleaned it and installed the plug and it is still bucking so I will replace the spark plug tomorrow. Since I will be at Orielly's, I will see if they have a fuel pressure tester to check my injectors. Hopefully this will get resolved.

 

[docraymund]

Also buy a spark tester to actually verify the firing of that cylinder. And ask if you could rent a compression tester to verify if it's a dead cylinder.

 

[1955moose]

I agree with doc, on both items. Be sure you don't have a leaky valve, or non functioning injector. If power to the injector and coil check out as well as sufficient compression, pull that injector, to be sure it's spraying proper fuel. Injectors clog up easy.


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[Snag]

I think DO and Moose have you on the right path. Doing a compression test is critical on these fuel injected engines when you have driveability issues. With low compression you can have this code with brand new plugs and COP's. Way back in the day my mechanic teachers always told us to start with the basics, every engine needs compression, fuel and spark to run. The modern engine is certainly more complicated then that, but still these basics have to happen. Pull a compression test, do all 8 while at it. Even a Harbor Freight compression tester will work.

 

[1955moose]

Or if they want to cheat, they can pull the plug to the crank position sensor, modern eq of distributor, and check that bank that's throwing the code. These motors are such a bear to pull plugs and try to screw in spark plug compression testers, knowing at least the coded one is ok.


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[Snag]

Everything about these modular engines is a bear. They are really not for the non mechanic or ones who cannot afford to keep throwing money at them. Once they start being a problem you better ditch them... I keep wanting to like the blue oval, but it is getting more and more difficult. Ford has made so many blunders with this modular engine series and the diesel engines that Old Henry would roll over in his grave. Now they are putting all their eggs in the basket of the v-6 turbo.

 

[1955moose]

I agree, I have two good friends, 1 has a 2001 Chevrolet Silverado with 140k no problems. The other a 2005 Toyota Tundra. Same deal 0 issues. I've been a Ford guy since 1986, but it's getting tough. You can only keep the public loyal so long. Does anybody remember the garbage 4 and 6 cylinder American cars that were being built in the 70's and 80's, I sure do. That's why company's like Toyota, Datsun, Honda outsold us. Hell even Red Forman drove a Datsun 210 on that 70's show, while his son Eric drove the Olds vista cruiser. American company's have got to start paying attention again. Or we're heading for the same crossover to the other side of the pond as before. When's the last time you heard of a Tacoma spark plug breaking, or spitting out of its cylinder?


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[Snag]

You called it Moose. I agree 100%. I didn't want to get in trouble by talking of other rigs then Ford. Some of these sites are brutal when you say anything against the badge. I have no idea how Ford has been the #1 seller for 30+ years. The Chevy LS engine is far superior to the modular engines and I am not a Chevy fan, don't own one. OK there I said it. I also have a 2004 Dodge 1500 4 door 4x4, and yes with the Hemi. 178k bought it new and I have only maintained it according to the book. Finally put brakes on it at 150k because I felt guilty and just replaced the battery this past Thanksgiving because I was going to Montana and didn't want to get stuck out in the middle of nowhere and die.... The only mechanical thing I had done due to CEL was replaced the EGR valve, that was like 42.00 and 30 minutes. I could have cleaned the original and it would have worked, but thought what the heck, replace it.

Yes, the Asain rigs are kicking our butts again IMO. If we don't get it figured out Toyota will be the World market leader, may already be and the others not far behind. I would never buy another Ford if I wasn't able to work on them myself. I feel bad for these guys who are getting on site because they just bought a Exp and it is ticking or smoking, they are going to get a hard lesson to learn.

And yep, I certainly remember the junkers of the 70's, 80's and early 90's. I cut my teeth working on them. We gave Asia an open window to show us how to make a rig. Wait until China hits the markets with something. Unless old Trumpster puts a tax on Imports to level the playing field they will soon all be kicking our butts. You and I both grew up when in the 60's anything Asain made was a big joke. By the mid 70's we started saying, hey these rigs are pretty simple and run forever. China IMO is cutting that learning/quality curve in half. I hate to say it but all the parts I have bought from them look as good or better than the Ford parts I am replacing. The repairs on my 05 KR the only factory replacement parts I used were the lash adjusters and followers. The damn followers looked like someone made them with a torch and anvil, very, very rough.

Been great talking to you, some old farts going through old memories

Gary

 

[OXX1973]

Sorry for taking so long to get back to everybody. I have finally fixed the issue. I was on my way to buy a new spark plug when the cel came back on, My code reader pulled up a miss in cylinder 1 this time. This was my fault because I replaced the COP from cylinder 1 to Cylinder 3 but before I put the COP in cylinder 1, I noticed the boot was cracked at the bottom where it contacts the plug. I pulled the boot and replaced it with one that looked pristine (I guess looks can be deceiving) from one of the COPs I replaced. Once I pulled the boot off and replaced it with a new store bought boot everything clicked and now she runs smooth.

I did run some of the tests with the borrow tools at part store but they did not have all the tools I needed to run all the suggested tests. I will have to buy them at a later point.

Thank you to everyone that helped me.

 

[1955moose]

This is why you replace the spark plug boots every time you change plugs, every 100k. They are a wearable item, just like the spark plug wires of past. The heat along with any coolant leaks shorts them out. In the future keep an extra new/ known good one in your tool box. You can also do an ohm test if your inclined. Do the test on a new one for a reference, but it's posted online, the spec.


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[Snag]

Another good call Moose. Many, many COP's have been thrown away and for the most part they are a life time wear part. Those rubber boots I bet are 95% of the problems with miss fire. New boots and a little silicon electrical grease are golden.

I changed all mine out to pretty yellow ones. Even at 60 I love fashion :O)

Thanks OXX for getting back to us, I really appreciate

 

[1955moose]

I can count on one hand the amount of coils I needed to replace over the years. Two of them were motorcycles due to vibration breaking them. I have had numerous spark plug wires fail. Guys when you notice a coolant leak, get on it right away. Water and electricity don't mix. In the old days we used to check arcing wires or distributor caps at night. You could actually see and hear it crackle. If you look online theirs a ohm spec test for both the coil , and the wire.


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