replaced the cyl heads, and ever since, i got it back, there is a popping, or backfire, only when in drive, nothing in nuetral, even while giving gas. Reverse doesnt do it either. Replaced 2 fuel injectors and a coil. Not hesitating, or nothing else noticable. Replaced all the plugs again, and nothing. only throwing code P1684. what else could possibly go wrong at this point? idles smooth, could it be a sensor? Its been a month long headache. please help

 

P1684 Metering Oil Pump Position Sensor Circuit Malfunction

BUT.. it sounds to me like its off time.. might have either put the timeing back on a tooth or 2 off.. or skipped.. did you use the same timing belt?

 

dish wrong code read out my friend the 1684 for an 02 RS van would be for teh tranny U need a good scanner that can get into teh tranny computer and see what that codes are.