Exactly the reply I was hoping to read sir t2erns! Yes the car is an Explorer FFV. From dec 2011 to Nov 2012, we religiously loaded Seaoil e85 on it. Seaoil has the only e85 fuel loading station in the country. Sometimes, i gas up there among racer with modified e85 capable engines

Problem started when the Explorer is brought to Baguio. Like the gas guzzler car that it is, it's impossible to run a full tank e85 to and fro Manila. And so we loaded regular gasoline somewhere in La Union. After 2 weeks, the rough idle started to show. We had it serviced at ford casa, they only changed the oil, oil filter, air filter. As if asa pa kami lol. After 3 days it went back, and so we brought it a 3rd party service center, they recommended changing all the plugs. We changed it, and for 2 months no rough idle.

Then it went back again. I read somewherr na when ethanol stays too long in the engine, it attracts moisture in the air and therefore, engine may contaminate with water. Since e85 is 85% ethanol, just imagine the possibility of it attracting more moisture than regular e10. I had this theory coz the car is rarely used. It sits most of the time in the garage coz it's gas guzzler. Im thinking maybe there is some water contamination na.

Rough idle got worse, when my dad loaded regular gasoline from provincial gas stations either shell or petron, or kung san sya abutan. I figure it was the dirty fuel. And so i had the fuel filter changed. Imagine my surprise, the fuel filter located somewhere in the underchassis, was never replaced not even once, and this car had always been casa maintained for 8 years. That's how incompetent Ford casas are tsk tsk.

After replacing the fuel filter, rough idle is intermittent na lang, mostly after a fill up. Gumanda na din ang takbo ng makina. It's on a full Petron Blaze diet (0% ethanol) for a month now. kaya lang from time to time bumabalik ang sickness kaya that's why i eyeing the ECU or PCM, ano kaya ang solusyon dito. Reflash lang? The obd scanner that im using is generic but it doesnt report any error codes.