bhorse

It might disappear for a week. Then it's back. Backfire through the exhaust. It's not constant; it comes and goes at all RPMs. At a steady speed I can feel the car switch from running ok to running great. Fuel pressure holds at 40 no fluctuation. 1989 5.0 mostly stock.

Has anyone had this particular problem? What did you do to fix it?

mustangsneverdie

it sounds like to me that your runnin rich

FuzzyDiceRule

check the timing, sounds like your TFI module/dizzy might be bad

bhorse

The ghost is still in the machine but here's what I've done so far.
Went ahead with the distributer and TFI and the indicial test seemed to change the situation. But at 4000 RPM the thing acted like I had a rev limiter on it. At that point I hooked up a new coil and bingo, revved it up to 5000 no problem. YEE HAW! Or so I thought. Heading home two blocks away and POP POP. Also cutting out at around 4000 again.

This morning I found the PVC out of the grommet so I think surely I'm onto something now. Put it back in, test drive one POP and I'm still at square one. Thankfully I have most of these parts sitting here.

What would be the result of a bad PVC?
Would a malfunctioning injector do this?

Any help is much appreciated.

mjr46

it's possible^^^^^^^^^^ also check the plugs and make sure they are not fouled

mjr46

may have a bad stator in the dizzy