Intermittent Flashing CEL
12-02-2016, 02:40 AM
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Intermittent Flashing CEL
My truck is a 1988 F150 2wd with the 4.9l i6 and Mazda 5 speed, it has 203k miles on the engine, no internal work ever done. The latest issue I have been experiencing is an intermittent flashing cel, I cannot get the truck to throw the code with a scan tool hooked up so I have no way of producing the exact code. The problem occurs only while under acceleration. Not heavy acceleration, but when the pedal is around half way to the floor. If i take my foot off the pedal or floor it the light stops. Some days I will not even see a light at all. I'm not sure if this could be a factor in this problem, but I replaced the injectors a few weeks ago. This may or may not have something to do with it also, but for a while I have had a rough idle that shakes the vehicle. I suspect a miss, but have not gotten the chance to do much diagnosis. I am looking for suggestions of what the problem may be, Sorry if this post doesn't make too much sense.
Last edited by Radeckiwesley; 12-02-2016 at 02:43 AM.
12-02-2016, 03:14 AM
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Intermittent misfire. Could be a number of issues. Spark plug condition, wireset, cap/rotor, something along the lines of those. An old Dodge of mine had a hit and miss misfire... Caused by low compression on one of the cylinders. It'd come and go depending on how much I felt like beating on her. Heavy on the throttle, it'd come back almost instantly and only miss at idle and low RPM. If I babied it for a couple days, it'd go away. No clue what was causing it as I sold the truck before I ever got the chance to really look into it.
12-02-2016, 03:19 AM
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All the things you mentioned have been replaced recently, it sounds like I really need to find the time to do a leak down test. Low compression is what I expect to be the culprit of a misfire
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12-02-2016, 03:30 AM
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I only got the truck 1 year and 12k miles ago, the previous owner was an old man who let it sit in the driveway most of the time. If the appearance has anything to do with how it was ran then I would say it was ran very easily. I do run vehicles pretty hard though.