Engine Shudders when driving at high speeds

My Expedition started to shudder on a drive when I got it up to 55 MPH. I drove for about 15 minutes and parked well I drove it again and it started to do the same thing. Now the Service Engine Light came on. Any suggestions of what the cause could be. (2000 Ford Expedition EB Ed. 5.4l Triton.

The service engine light holds the starting point for figuring it out.

Many auto parts stores will read the error codes for free. Have them read, write down the exact code (like “P1234”) and post them here. Don’t bother with what the auto parts guys say, just report the exact codes.

When you come back with the codes also report all other details about the vehicle that you have - mileage and the state of basic maintenance items (plugs, wires, filters, etc.)

How many miles on it and when were the plugs and wires changed?

P0306 I read it was cylinder 6 misfire. It currently has 91,411 miles on it. Changed the oil filter about 3 months ago same with the air filter. Spark Plugs were changed about 2 years ago at about 85,217 miles. 5.4l Triton I live in Alaska its cold about -25. It is winterized, it has made a trip from Oregon through Canada to Alaska about 2600 miles did not have a problem. Oil light keeps coming on and then off, the needle fluctuates but has the proper amount of oil and all the other fluids.

Now the Service Engine Light came on. Was that CEL or SES (service engine soon)

 That CEL (check engine light) is just a kid in class waving her hand trying to get you attention because she has the answer. You need to have the codes read. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.

Possible Good News On Your Oil Pressure: There’s A TSB By Ford That Indicates Your Vehicle (With 5.4L) May Have The Oil Pressure Sending Unit Contacting The Engine Oil Drip Shield And Causing A Malfunction Of The Sending Unit.

Some sending units need replacement and the oil shield (removed from front axle - 3 bolts) gets “modified” by trimming just a little material (8mm) from one edge and eliminating sharp edges and reistalling, so that the contact stops.


P0306 is what it said. I read it was a Cyl 6 misfire on the internet.

also it is a Service Engine Soon light.

Thanks I will get under there and check it out.

The oil light is very bad and hopefully you just have the problem CSA mentioned rather than an actual pressure problem. But I do think it means that a compression check is in order.

The first place to look for misfire problems is just at plugs and wires. The plugs aren’t that old so they should be fine - but the #6 should be pulled and inspected. Were the wires replaced when the plugs were? If it can be made to work (given varying lengths) you can easily swap the #6 plug wire with another one. If the misfire follows the plug wire, replace them all.

If nothing comes of that you’d want to check the compression, obviously looking at #6. I’d actually just pull all the plugs to look and run compression checks while the plugs are out.

If the plugs and wires and compression are all good you look deeper into the ignition system - this engine probably uses a coil pack and that should be checked. And you also need to check out the fuel injectors. Simple visual inspection of the wiring harness is a good place to start. The resistance on an injector is also easy to check. If basic checks work out, you can swap the #6 with another and see if the misfire follows the injector.

When You Take A Look, Keep In Mind That The Engine Has Some Movement In Its Mounts When Operating. Look For Circumstantial Evidence Of Contact / Contact Damage.


So I did some work and checked the connection and wouldn’t you know it the connection was loose and that seems to have been the trouble. Thanks to everyone for the input.

I assume that the loose connection thing is about the oil light issue. This won’t cause a misfire. Did you figure that out?