Service Engine Light

I have a 2002 F150 with a 4.2 and the service engine light is on. The code is a vacuum leak, or so I was told. The place that used the scanner said that it was most likely the intake gasket and bolts that it was a pretty common problem on the 4.2's. Anyways they had cleared the code and it was off for about 3 days when it came back on. The truck isn't running rough or idling rough and runs smooth. My question is, this a common problem on the 4.2's and if it is the intake gasket leaking wouldn't that have tripped the code right away after it was cleared?

Thanks, Steve

Reply to
MrBlues
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You need to know the code. Period.

Armed with the code, we can help you with greater accuracy. Having said that, the Evaporative Emissions Control System (the system that looks at leaks in the gas tank and its related vacuum systems) will throw codes in the range of P0440 to P0459.

If you bought gasoline immediately prior to the Check lamp coming on, odds favor poor locking of the gas cap. The gas cap has a ratchet mechanism, and one should ALWAYS make the ratchet click several times to seal the cap. It is true that the problem _could_ be a serious one, but I'm gonna hang my hat on easy and cheap for now.

Whenever you have codes pulled, you should jot them down. I'm prone to resetting the codes and waiting to see if they come up again, If the light comes back on, and the code is the same then I have a good idea where the problem is. If the light comes on but the code is different, then I have to check the list to see if the code is in the same family, if so then I have two data points from which to search for stuff to fix. All codes are arranged into families, and a loose gas cap is in the family stated earlier. A loose cap can result in any of several codes within the same family, from a simple description of "malfunction" to a more complex description of "gross leak." You may have two or more codes from the same family, so your diagnostic skills must include the ability to draw a line of commonality that hits as many of the same part as possible. A malfunction and a gross leak and a minor leak can all stem from a poorly sealed gas cap. Get it?

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Reply to
Jeff Strickland

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