Thread: Injectors on 3.9, replace or clean ?

Well it's really up to you.
The 3.9 injectors are by now a very old design with a single outlet , while most newer injectors have at least 4 tiny holes to give better atomisation.

I have fitted new Bosch gen2 injectors (pink) that suited a Ford 4.6 and are nearly the same output as the Lucas ones for about $280 AFAIR .

I have since fitted Gen3 Bosch (yellow) that I bought reconditioned from the USA for about $120 for the set .

However I have fitted o2 sensors which even out any differences, but it should not make too much difference even without them.

The major pluses of the new injectors are smoother more stable idle , but I have not noticed any difference in economy.

If your old Lucas ones are dying, you may find that you lose one or more in the cleaning process. This becomes expensive as you have to pay for new injectors to match the rest and they are EXPENSIVE. Ask me how I know, I lost 2 being cleaned.
So on balance I would go (and have gone) for new . There are lots on US ebay and Fiveomotorsport I have dealt with for new.
Fuel Injectors, Performance Injectors | FiveOMotorsport

Reco you look for 4.6 Ford and Bosch. gen 3 are yellow, but need a second o ring as they do not have a top spring retainer like the Lucas. Gen 2 are probably better as they have the retainer clip provision.

Regards Philip A

Here is an ebay reference.
The ones you want are 19lb per hour

1991 FORD MUSTANG GT 5.0 HO BOSCH 19 # LB FUEL INJECTORS UPGRADE | eBay
Regards Philip A

Hi PhilipA, I've just received a set of Bosch Gen3 injectors, where exactly do I need to fit the extra o-ring, and what size is it.
Cheers!