i have 2002 model sport trac with 71237 kilometers on it...check engine light illuminate and the com reading exhaust gas insufficient flow...reset then out for sometimes and back again.Til now,engine check it there and no problem on starting and driving,as well.the no start issue,is right after a big lightning on the night.the next day when i about to use the car,wont start...any idea to solve my predicament?

 

Welcome to the forum!

The diagnostic code for EGR flow insufficient could be pointing to an issue with the Differential Pressure Feedback EGR (DPFE) sensor. That used to be a pretty common issue with Fords, but I don't recall hearing about as many of them failing by the 2002 model year.... I would not be surprised by a rough idle and misfire if the DPFE sensor were the issue, but I would be a bit surprised by a no start due to it. Do you know if that code were present before the no start problem?

Often issues following rain storms are due to moisture getting somewhere it's not supposed to get. A faulty Crankshaft Position (CKP) sensor or issue with that circuit could cause a no start condition, but at this point I'm just guessing. It could help greatly narrow the likely source of the no start condition if you could determine if your truck is missing spark, fuel, or if it possibly has low battery voltage. It is possible to have enough charge to turn the starter motor over but not enough to keep the engine computer "happy".

-Rod

 

The engine check start the following day when i replaced the oil seal on the differential,because it was leaking a bit.the diagnostic code say exhaust gas insufficient flow.

i replaced the spark plug with auto lite platinum,but still the check engine appreared after a two day or one day drive.same code,and the mechanic reset.again it appeared after aday or two.the mechanic installed back the original motocraft brand spark plug coz its still good.But he remove the battery connection when removing it.right after he's done,i started the car with rough idle...he say give it a drive and the computer adjusted itself.the next morning it did not start after 3 or start attempt.And it did start with a rough idle,driving is ok.no issue for starting.But after 2weeks,it did not start at all...suddenly with no symtoms...

Please share if u have ideas on my predicament...

 

It sounds like the guy either didn't get a spark plug wire installed correctly, or he cracked a spark plug in the process of reinstalling them, causing a misfire.

I don't see any way the EGR flow code could be related to swapping a differential seal, but it could be related to the spark plug change. The vacuum lines for the DPFE are in the vicinity of the spark plugs and if one of the hoses was already brittle, could have easily cracked during the plug swap.

-Rod