AndyG414

I have a 1998 Ford Expedition Eddie Bauer 5.4L 2V with 137K on it. After I returned from Thanksgiving break my truck starting to randomly misfire on the freeway at 70 MPH and at 2K RPM. It only happens on the freeway and under acceleration. The CEL flashes but does not stay on, I scanned it and got no codes at all for it. I'm wondering if it is a coil, but I have no way of pinpointing which one it is, and at $60 a piece I really don't want to replace all 8. Does anyone have any suggestions?

Bert

Usually you'll get a P0300 for random mistire. If the light came on, there should be a code stored. Has the fuel filter been changed recently? Read this, OBD-II Trouble Code: P0300 Random/Multiple Cylinder Misfire Detected

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Bert

CatSkinner

If you're misfiring, pull the plugs, the gummy one will be the culprit... or victim of the misfire.

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Prius repellant, just add gas.

paul1234

Just to let you know it requires a spcial socket to install the plugs. It cost me $600.00 to find that out. Also this might be the time to take it to the dealer they have the equipment to test the coils. I had a bad coil and cracked two plugs when I tried to change the plugs. The shop I used didn't have a tester for the coil. An expensive lesson learned. Good luck

bucherba

I also had a 98 Expedition, and when I'd encounter the misfire the CEL wouldn't light at first until the miss was bad enough. I found it strange that the misfire codes ARE NOT STORED. You have to have them read while the CEL is lit, but it will tell you exactly which cylinder is mis-firing.....no guess work. It's just a pain to try and get it read while lit, but if it's on, don't turn off the engine, and get to AutoZone...ect and have it read. Once again, the misfire codes on the 98 Expy don't store!!

Bert

They store but you need a scanner that will check for pending codes and they cost more than a regular scanner.

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Bert

CatSkinner

My scanner will do it and it onlty runs about 140 bucks at Advanced. It's an Actron.

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Prius repellant, just add gas.

AndyG414

I used a Matco Determinator scan tool while I was driving down the free way, my friend was in data stream and nothing came up. I have not changed the fuel filter recently. Also I think you are right and I should inspect the coils and plugs for damage and wear.