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1999 Ford E150 Van P0302 Misfire: Is a Loose Fuel Cap the Cause?

Model: 1999 Ford E150 van Fault Code: P0302 Posted: 2010-04-16 14:09

I'm experiencing an intermittent P0302 code indicating a misfire in cylinder #2 on my 1999 Ford E150 van. The engine light flashes, then stays on, and I notice occasional hesitation or sputtering during cruising—this typically resolves when I restart the vehicle. After adding fuel system nozzle cleaner, I discovered that the fuel cap had not been properly tightened during a previous fill-up. Both OBD2 scans show the same P0302 code. The van is currently running smoothly, but the check engine light remains on. Given that it has 85,000 miles and a 4.6L engine, I'm wondering if a loose fuel cap could be responsible for this misfire. Would a loose fuel cap trigger a P0302 code? If so, is this a common issue at this mileage? I’m hesitant to replace spark plugs or wires—wouldn’t that result in a constant misfire rather than intermittent behavior? How difficult is it to replace these components on my own? What would be the typical cost for parts and labor in Delaware if I choose professional service? Can I clear the P0302 code without using a handheld OBD2 scanner? I have a DMV retest coming up at the end of the month, so any advice would be greatly appreciated. — BobMach

Related fault codes
P0302
Comments (3)
Anonymous 2010-04-17 07:54

A loose fuel cap does not cause cylinder misfires like P0302. It may affect evaporative emissions but not engine misfire. At 85,000 miles, a tune-up is reasonable—especially for a 4.6L V8 engine. Try swapping the #2 coil over to another cylinder (e.g., cylinder #3) and see if the code changes. This helps determine whether the issue lies with the coil or the spark plug. If you replace any components, use OEM parts such as Motorcraft coils and Autolite plugs—these have proven reliability in preventing recurring issues. Consider replacing all spark plugs during this service to ensure consistent performance.

Anonymous 2010-04-17 08:33

Thanks for the clarification! You're right—I meant swapping the #2 coil over to a different cylinder, such as cylinder #3, to see if the P0302 code changes. The original issue was cylinder #2 misfire, so that makes sense. I’ve heard about spark plug reliability issues in some Triton V8 engines—thanks for confirming that Motorcraft coils and Autolite plugs are more reliable and help avoid reoccurrence.

Anonymous 2010-04-17 08:37

Apologies—I meant to say 'swap the #2 coil over to cylinder #3' as a diagnostic step. This is something we’ve seen before when trying to save customers money with non-OEM parts—using Motorcraft coils and Autolite plugs has significantly reduced return issues in our shop.