QuestionI have a 98 caravan with a3.3 flex fuel engine. 6 weeks ago it started to miss and backfire about 3 minutes after start up until the engine was fully warmed up. it has been to a shop 3 times for diagnosis. There was never a code so they had me try replaceg fuel filter, crank sensor, plugs, plug wires, thermostat, temp sensor, egr valve, 1 oxegen sensor. The dealership told me to run 3 tanks of gas through the tank to eliminate all the ethenal in the tank. It was at 30 percent.there has been no improvement. any sugestions would be appreciated.
Thanks Tom
AnswerHi Tom.
What you describe is a problem that occurs with E-85. I don't have personal experience with that but the manual states that mixing the fuels is undesireable. The suggestions are to not switch very often and WHEN YOU DO:
be sure that when you switch there is not less than 1/4 full showing on the gauge, do not add less that 5 gallons when refueling, operate the vehicle for at least 5 minutes after refueling. Otherwise there is going to be hard starting or deterioration in driveability during warm up. And if it is above 90F you may still have problems even if you observe the above recommendations.
Other that that, it sounds like you tried everything I would have suspected plus more. Please let me know if it turns out to be something unusual.
The E-85 is not good below 0, and is still hard to use up to 32F while the engine is warming up.
I'm in California so I haven't seen this product for sale nor do I hear about these difficulties. I notice that there is a 'flexible fuel sensor' wire into the electronic control system but no discussion of it's function or location but I would wonder if that might be the source of the problem?
Roland
