Removed the fuel rail while doing my plenum pull and lo behold I think I know why my car was backfiring when decelerating. I think because the plastic insulators on two of the injectors were broken they were leaking. I guess these need to be replaced?
That's nothing mate, they replace the pintle cap with an injector service anyway... I HIGHLY recommend you get all of your injectors fully serviced and flow tested before putting them back in. A good EFI shop should do them for around $30 an injector.
Make sure you get them all done, injectors over time get extremely blocked up and they dont spray evenly. This can cause running problems but more importanly can lean out cylinders when it gets really bad. Just make sure they give them a full service and clean...
No, the pintle caps will not cause any problems with your fuel delivery. You can run without them quite happily.
