|
When you say it "Back fires", do you mean it pops back through the intake or do you mean it pops out the exhaust?
Super lean mixture can cause a true back fire through the intake, and then a super rich mixture can backfire through the exhaust.
A backfire through the exhaust simply from a super rich mixture, is most likely going to happen on throttle lift while decelerating, not while cranking from the starter.
I know you said your shop checked the CDI box, but mine did the very same scenario when my CDI box was dying. Although my symptoms where on again/off again for about 2 days before it finally gave up the ghost for good. It would run fine for a long time, then crap out for no rhyme or reason. Let the car sit and cool down, it would fire up and run just fine for a bit, then act up again.
So just because they checked it once, does not mean your CDI box is actually good. Have your shop temporarily swap out the box for another, and see if that solves your problem.
My .02 worth.
Mark
|